to define the housing 202. In the illustrated embodiment, the mounting system 210 includes a leg 216 (a “mast”) and a base (a “mount,” not shown). The base may be securable to a surface and configured to receive a bottom portion of the leg 216. The leg 216, shown as a single mounting leg, may be defined by a generally hollow cylindrical or tubular body, although other shapes may be suitably employed. With a hollow configuration, any necessary wiring or electrical connections may extend into and within the interior of the leg 204 up into the housing 202 of the antenna apparatus 200.

A tilting mechanism 240 (details not shown) disposed within the lower enclosure 204 permits a degree of tilting to point the face of the radome portion 206 at a variety of angles for optimized communication and for rain and snow run-off. Such tilting may be automatic or manual.

Returning to FIG. 1, the antenna apparatus 200 is configured to be mounted on a mounting surface for an unimpeded view of the sky. As not limiting examples, the antenna apparatus 200 may be mounted at an Earth-based fixed position, for example, the roof or wall of a building, a tower, a natural structure, a ground surface, an atmospheric platform or balloon, or on a moving vehicle, such as a land vehicle, airplane, or boat, or to any other appropriate mounting surface having an unimpeded view of with the sky for satellite communication.

In various embodiments, the antenna apparatus 200 includes an antenna system designed for sending and/or receiving radio frequency signals to and/or from a satellite or a constellation of satellites. The antenna system, as described below, is disposed in the housing assembly 202 and may include an antenna aperture 208 (see FIG. 2A) defining an area for transmitting and receiving signals, such as a phased array antenna system or another antenna system. Besides the antenna aperture 208, the antenna apparatus 200 may include other electronic components within the housing assembly 202, for example, which may include, but are not limited to beamformers, a modem, a Wifi card and/or Wifi antennas, a GPS antenna, as well as other components.

Turning to FIG. 3A, the antenna apparatus 200 may include an antenna stack 250, an internal cover 252, a lower enclosure 204, and a tilting mechanism 240 coupled to a leg 216. The leg 216 may extend through an opening 254 defined by the lower enclosure 204 and may couple to the tilting mechanism 240. A volume 258 may be defined between the antenna stack 250 and the lower enclosure 240. The internal cover 252 may be coupled to the lower enclosure within the volume 258, forming an inner volume 256 between the internal cover 252 and the lower enclosure 204. The coupling between the internal cover 252 and the lower enclosure 204 may be waterproof or water resistant (i.e., the internal cover 252 may be hermetically sealed to the lower enclosure 204), and the opening 254 may be defined within the inner volume 256. In that regard, any debris or moisture that enters the inner volume 256 via the opening 254 may remain within the inner volume 256, reducing the likelihood of such debris or moisture reaching the remainder of the volume 258 (including the antenna stack 250).

The tilting mechanism 240 may be coupled to at least one of the lower enclosure 204 and the internal cover 252 such that rotation of the tilting mechanism 240 relative to the leg 216 results in rotation of the antenna stack 250 relative to the leg 216. Such rotation may be used to physically adjust of the position of the antenna aperture 208.

FIG. 3B illustrates an exploded view of the antenna apparatus 200, showing various layers of the antenna stack 250. For example, the antenna stack 250 may include a radome assembly 305 which may include a radome body assembly 310 and an outer layer 315. The antenna stack 250 may further include a patch antenna assembly 334 that includes an upper patch antenna layer 330, an antenna spacer 335, and a lower patch antenna layer 370 which together form a plurality of patch antennas forming an antenna array. The antenna stack 250 may also include a dielectric layer 375 and a printed circuit board (PCB) assembly 380. As will be discussed further below, the various layers of the antenna stack 250 may be at least partially mechanically and electrically coupled together.

As shown in the illustrated embodiment, the layers of the antenna stack 250 may be rectangular in shape. That is, each of the radome assembly 305, patch antenna assembly 334, dielectric layer 375, and PCB assembly 380 may have a rectangular shape when viewed from above or below (i.e., along a stacking axis of the antenna assembly 250). However, one skilled in the art will realize that the shape of the antenna stack 250 (and all elements therein) may have any shape such as rectangular, square, circular, oval, square, and the like, and may have any additional features such as rounded corners, sharp corners, and the like. As shown each element of the antenna stack 250 may have similar lengths and widths (as well as the lower enclosure 204). As will be further discussed below, the radome assembly 305 may have a slightly greater length and a slightly greater width than the remaining elements of the antenna stack 250 to facilitate coupling of the radome assembly 305 to the lower enclosure 204 in such a manner to cause the remaining elements of the antenna stack 250 to remain wholly enclosed within the volume 258. However, one skilled in the art will realize that the various layers may have different dimensions.

Radome Assembly

Referring to FIGS. 4A, 4B, and 5, various additional features of the radome assembly 305 are shown. As seen in FIG. 5, the radome assembly 305 may include an inner end or portion 403 that is located nearest the lower enclosure 204 when the antenna apparatus 200 is fully assembled (e.g., see exploded view in FIG. 3B) and an outer end 401 located opposite the inner end 403. As shown, the radome assembly 305 includes a radome body assembly 310 (which may extend to the inner end 403) and an outer layer 315 (which may be located at the outer end 401). In some embodiments, the radome body assembly 310 and the outer layer 315 may be referred to as a radome. The outer layer 315 may be exposed to the elements when the antenna apparatus 200 is fully installed and, thus, the outer layer 315 may include water or other weatherproofing features, as described in more detail below.

The radome assembly 305 is designed to be an outer portion of the antenna apparatus 200, which is exposed to the outdoor environment and has mechanical properties of good strength to weight ratios, and a high modulus of elasticity for stiffness and resistance to deformation. Where referred to herein, discussion of the radome assembly 305 may refer to any one or more component of the radome assembly such as at least one of an outer layer 315, a radome body portion 402, a radome spacer portion 404, elongated members 400, and the like. So as not to impede RF signals, the radome assembly 305 has electrical properties of a low dielectric constant, and a low loss tangent. In addition, in some embodiments, the radome assembly 305 has chemical properties, for example, of bondability for bonding with adhesive, UV resistance, and low or near zero water absorption. The radome lay-up can also have other suitable properties to mitigate vulnerability to constant outdoor exposure and extreme weather conditions.

The radome assembly 305 is designed to maintain high mechanical values and electrical insulating qualities in both dry and humid conditions over thermal cycles between −40 degrees Celsius (° C.) and 85° C. In some embodiments, the radome assembly 305 has a relatively high yield strength and a relatively high enough modulus to spread load on various portions of the radome assembly 305. In some embodiments of the present disclosure, the radome assembly 305 has a dielectric constant of less than 4. In some embodiments of the present disclosure, the radome assembly 305 has a loss tangent of less than 0.001.

The radome body assembly 310 may include multiple portions, or components, which may be formed integrally or monolithically (e.g., from a same piece of material or collection of base materials and formed together) or, in various embodiments, may be formed separately and coupled together in any known manner. For example, the radome body assembly 310 may include any one or more of elongated members 400, a radome body portion 402, and a radome spacer portion 404. As will be described in further detail below, the elongated members 400 may be used to couple the radome assembly 305 to additional layers of the antenna apparatus 200. For example, a distal end 470 of the elongated members 400 (i.e., located at the inner end 403) may extend through some or all layers of the antenna stack assembly 250 (see FIG. 3B) and may be deformed or otherwise manipulated to resist separation of the various layers after assembly (e.g., see assembly of the antenna stack assembly 250 in FIG. 10).

In some embodiments of the present disclosure, the radome body assembly 310 may be constructed of a fiberglass base for mechanical strength. The fiberglass may be laminated with a polymer or copolymer of polyethylene, which may be functionalized with fluorine and/or chlorine. The laminate may be a fluorinated polymer (fluoropolymer), such as polytetrafluoroethylene (PTFE) or a copolymer of ethylene and chlorotrifluoethylene, such as ethylene chlorotrifluoroethylene (ECTFE). The radome body assembly 310 may be fiberglass-reinforced epoxy laminate material, such as FR-4 or NEMA grade FR-4. In other embodiments, the radome body assembly 310 may be another type of high-pressure thermoset plastic laminate grade, or a composite, such as fiberglass composite, quartz glass composite, Kevlar composite, or a panel material, such as polycarbonate. As described in greater detail below, the radome assembly 305 may include a top hydrophobic surface for water removal.

In some embodiments of the present disclosure, the radome body assembly 310 may be a lay-up made from a first layer made from fibrous material, such as fiberglass or Kevlar fibers, pre-impregnated with a resin, such as an epoxy or polyethylene terephthalate (PET) resin.

In some embodiments, the radome body assembly may be formed from a plastic with a plurality of fibers located throughout. For example, the fibers may include fiberglass, Kevlar fibers, carbon fibers, or the like.

The radome body assembly 310 may also include a radome body portion 402. The radome body portion 402 may include a planar surface that extends across an entire width 408 and length 410 of the radome body assembly 310. The radome body portion 402 may have a rectangular shape, or may include any other shape such as circular, elliptical, square, or the like. The radome body portion 402 may provide structural support to the outer layer 315, may at least partially protect additional elements of the antenna stack 250 (see FIG. 3B) from elements in an environment of the antenna apparatus 200, and may be formed from a material through which antenna signals may travel (i.e., the radome body portion 402 may fail to interfere with antenna signals). The radome body portion 402 may have a planar top surface 412 and a uniform thickness 414 throughout. However, in various embodiments, the radome body portion 402 may have a curved top surface, may have a non-uniform thickness, or the like.

The thickness 414 of the radome body portion 402 may be in the range of less than or equal to 60 thousandths of an inch (mil, 1.5 millimeters (mm)), less than or equal to 30 mil (0.76 mm), less than or equal to 20 mil (0.51 mm), or less than or equal to 10 mil (0.25 mm). The thickness may depend on the conditions of the environment in which the antenna apparatus 100 resides, for example, with a greater thickness 414 being used in geographic locations having harsh weather conditions, such as heavy rain and hail. However, a reduced thickness 414 may reduce radio frequency (RF) signal attenuation from the antenna array. In one embodiment, the radome body portion 402 has a thickness of 0.5 mm.

In some embodiments, the radome body portion 402 and the outer layer 315 may be referred to as a radome. In some embodiments, the radome body portion 402 and the outer layer 315 (or the radome body assembly 310 and the outer layer 315) may be formed integral or monolithic and be formed from the same material. In other embodiments, the radome body portion 402 and the outer layer 315 (or the radome body assembly 310 and the outer layer 315) may be formed separately and assembled together.

The radome body assembly 310 may also include a radome spacer portion 404. The radome spacer portion may be made from the same or different material as the radome body portion 402 and may support the radome assembly 305 in providing mechanical and environmental protection to the antenna aperture 208 and other components of the antenna apparatus 200. The radome spacer portion 404 may also provide suitable spacing between the antenna elements of the antenna aperture 208 and the outer layer 315 of the radome assembly 305. As described in greater detail below, such spacing can provide advantages in reduced signal attenuation due to environmental effects on the outer top surface of the radome body portion 402, such as dirt, dust, moisture, rain, and/or snow.

In some embodiments, the radome spacer portion 404 is a plastic or foam layer having properties of low dielectric constant, low loss tangent, good compression strength, and a suitable coefficient of thermal expansion (CTE). In addition, the radome spacer portion 404 may have the property of bondability for bonding with adhesive for coupling with other layers in the antenna stack assembly 250.

As part of the radome assembly 305, the radome spacer portion 404 may also be designed to maintain high mechanical values and electrical insulating qualities in both dry and humid conditions over thermal cycling between −40° C. and 85° C. In some embodiments of the present disclosure, the radome spacer portion 404 has a dielectric constant of less than 1.0. In some embodiments of the present disclosure, the radome spacer portion 404 has a loss tangent of less than 0.001.

The radome body portion 402 may be adjacent or coupled to a radome spacer portion 404 to space the outer top surface of the radome body portion 402 from components of the antenna stack 250. In some embodiments, the radome body portion 402 may be formed monolithically with the radome spacer portion 404, or coupled to the radome spacer portion 404, for example, by adhesive bonding. As mentioned above, the radome body portion 402 and radome spacer portion 404 may together (alone or in combination with elongated members 400) be referred to as a radome body assembly 310. The radome spacer portion 404 may also have a planar and rectangular shape corresponding to that of the radome body portion 402.

As seen in FIG. 5 and in some embodiments, the radome spacer portion 404 may be thicker than the radome body portion 402. In accordance with embodiments of the present disclosure, the radome spacer portion 404 has a thickness such that the distance from the top patch antenna layer to the top of the radome in the range of greater than about 3.0 mm, less than about 4.5 mm, or in the range of 3.0 mm to 4.5 mm.

The radome spacer portion 404 may include a spacing configuration to space the radome body portion 402 from the antenna aperture 208 with air. As one non-limiting example, the radome spacer portion 404 may be made from foam material having air disposed within the structure of the foam. Foam spacers may be advantageous materials in some environments because of their lower dielectric constant and lower thermal conductivity. For example, in cold environments (such as cold climates or for antenna apparatuses 200 disposed on airplanes) foam spacers may provide an insulative effect for electrical components). One suitable foam may be a polymethacrylimide (PMI) or a urethane foam. However, other foams are within the scope of the present disclosure. Foams, unlike other materials described herein having thermal conductivity, may require separate heating systems for snow melt.

In other embodiments, the radome spacer portion 404 may be a frame structure. In one suitable embodiment, the frame structure may be designed to have air spaces within the structure of the plastic. One suitable frame structure may be a honeycomb structure. A suitable honeycomb structure may be made from a low-loss plastic material (such as thermoplastic or another suitable plastic material), which may be configured in a honeycomb frame construction.

In some embodiments, the radome spacer portion 404 may be air.

In some embodiments, the radome spacer portion 404 may include an interior portion 327 and an exterior portion 328 (see FIGS. 4A and 4B). In the illustrated embodiment, the interior portion 327 includes a plurality of cell walls 316, or cell portions 316, defining a plurality of apertures 317. The exterior portion 328 may extend around at least a portion of the outer perimeter of the interior portion 327, and may be a solid portion to assist in heat transfer around the outer perimeter of the antenna apparatus 200. In some embodiments, the exterior portion 328 may not be present. That is, inclusion of the exterior portion 328 may be optional.

Each of the plurality of cell walls 316 may extend away from the radome body portion 402. As seen in FIG. 5, the radome body portion 402 may have a first surface, or top surface 412, defining a planar surface at or near the outer end 401 of the radome body assembly 310 and a second surface 413, or bottom surface, opposite the first surface such that each of the plurality of cell walls 316 extends away from the second surface (and towards the inner end 403 of the radome body assembly 310). Each of the plurality of cell walls 316 may include an opening at the top (near the second surface 413 of the radome body assembly 310), an opening at the bottom (extending toward the inner end 403 of the radome body assembly 310), and a vertical pathway therebetween defining an aperture 317. Each aperture 317 is configured to vertically align with an individual antenna element in the antenna array to provide an airspace above each upper patch element of each antenna element in the antenna array.

A group of cell walls 316 and a single aperture 317 within the plurality of cell walls may together form a cell. In that regard, each cell in the embodiment shown in FIGS. 4A-5 may include 6 cell walls 316 and a single aperture 317 (e.g., a single cell 450 shown in FIG. 4B may include cell walls 451a-451f and a single aperture 452). In some embodiments, at least a portion of the cell walls 316 may at least partially define an adjacent aperture 317 of an adjacent cell. For example, the cell wall 451b may at least partially define a cell 456. One skilled in the art will realize that the cell walls 316 may have any shape (e.g., rounded, straight, angled, or combinations thereof), and that a cell may include any quantity of cell walls 316 (including a single cell wall 316 defining a single cell), without departing from the scope of the present disclosure.

In some embodiments, at least two cell walls 316 (or cell portions 316) defining a cell may be spaced apart from each other. For example, any two or more of the cell walls 451a-451f defining the cell 450 may be spaced from each other (e.g., cell wall 451a may be spaced apart from cell wall 451d). In some embodiments, any two or more adjacent cell walls 316 defining a cell may be spaced apart from each other. For example, the cell wall 451a may be spaced apart from adjacent cell wall 451b by a gap 453. Such spacing between cell walls 316 defining a cell may be referred to as a nodeless cell configuration.

As referenced above, cell walls 316 may have any shape. In such embodiments any two cell portions, or cell walls, 316 defining a cell may be spaced apart from each other. For example, if cell portions include two semicircular walls defining a cell then at least one intersection of the two semicircular walls may be spaced apart from each other. In that regard, each cell may have at least one gap defined by the walls that form the cell.

The cell walls 316 of the interior portion 327 radome spacer 310 may provide a greater proportion of air to mitigate any RF interference with antenna signals from the antenna array 308. In some embodiments, the volumetric ratio of air to solid surface area or the cell 316 of the radome spacer 310 is greater than about 50:50, or alternatively greater than about 65:45, or alternatively greater than about 75:25, or alternatively greater than about 80:20, or alternatively greater than about 85:15, or alternatively greater than about 90:10. Where used throughout in the present application, the term “about” refers to the referenced value plus or minus 10 percent of the referenced value.

As described above, the radome spacer portion 404 (or the entire radome body assembly 310) may be formed from a plastic or other polymer. For example, the radome spacer portion 404 (or entire radome body assembly 310) may include polypropylene (PP), polycarbonates, polybutylene terephthalate (PBT), polyphenylene ether (PPE), poly(p-phenylene oxide) (PPO), polystyrene (PS), polyethylene terephthalate (PET), polyvinyl chlorine (PVC), liquid crystal polymer (LCP), other polymers, or mixtures thereof. In some embodiments, the radome spacer portion 404 (or the entire radome body assembly 310) may include a plastic or other polymer with fibers (e.g., glass fibers) dispersed throughout. As will be discussed further below, such a configuration may provide a desirable coefficient of thermal expansion (CTE). The plastic may be molten with fibers dispersed therein, and may be injected into a part to form the radome body assembly 310. For example, the plastic may be injected into the radome body portion 402 at locations between the elongated members 400. In some embodiments, the plastic may be injected into the radome body portion 402 at locations where multiple cell walls approach (e.g., a first location 460). In some embodiments, the plastic may be injected into the radome body portion 402 at locations within cells (e.g., a second location 462). The plastic may be injected from the inner end 403, from the outer end 401, or both.

When forming the radome spacer portion 404 (or radome body assembly 310), it may be desirable for the fibers to be oriented in the radome body portion 402 to restrict thermal expansion of the radome body portion 402, and in the cell walls 316 of the radome spacer portion 404 to restrict thermal expansion of the radome spacer portion 404. FIG. 4C illustrates one embodiment of the orientation of glass fibers within the radome body portion 402 and the radome spacer portion 404. As shown, some glass fibers 454 that are disposed within the radome body portion 402 extend along a plane defined by the radome body portion 402 (i.e., they extend parallel to the planar surface defined by the radome body portion 402). These fibers 454 resist thermal expansion of the radome body portion 402 in a direction from the inner portion 327 to the outer portion 328 and provide for a planar top surface 412 of the radome body portion 402.

Some glass fibers 455 that are disposed within the radome spacer portion 404 extend along a plane defined by the cell wall 316 within which they are disposed. In particular, the glass fibers 455 may extend in a direction that is perpendicular to the plane of the radome body portion 402 (rather than in a direction that is parallel to the plane of the radome body portion 402). Such orientation of the glass fibers 455 reduces or restricts thermal expansion of the radome spacer portion 404 away from the radome body portion 402.

As will be discussed in further detail below, such fiber orientation within the radome body portion 402 and the radome spacer portion 404 provides a CTE that is similar to that of the other components of the antenna stack 250 such that any thermal expansion of components of the antenna stack 250 is relatively similar, which allows coupling of some or all components of the antenna stack 250 without adhesive (e.g., as discussed further below, such coupling may be achieved using the elongated members 400). CTE similarity provides various benefits and advantages such as allowing for relatively easy replacement of various components, reduced part count, reduced cost of manufacture, and the like.

The desired fiber orientation of the fibers 454, 455 may be achieved by the nodeless cell configuration described above. That is, the gap 453 defined between adjacent cell walls 451a, 451b results in the fibers 455 extending away from the radome body portion 402 in a direction substantially perpendicular to the plane defined by the radome body portion 402. Thus, the nodeless cell configuration of the radome spacer portion 404 results in fibers 455 extending in a direction substantially perpendicular to the plane defined by the radome body portion 402 and, thus, results in the entire radome body assembly 310 having a desirable CTE value and manufacturing result.

Radome Outer Layer

The radome assembly 305 may include an outer layer 315. RF signal attenuation due to gain degradation can be significant as a result of rain or moisture accumulation on the outer end 401 of the radome assembly 305, and the outer layer 315 may assist in reducing or eliminating such concerns. Regarding rain and moisture accumulation, water has a significant relative permittivity which can introduce a non-trivial interface for an antenna aperture causing RF reflection. Such RF reflection results in gain degradation in the RF signal.

Snow accumulation on the outer end 401 of the radome assembly 305 was generally not found to be as degrading to the RF signal power as water accumulation. However, snow with any moisture content was found to be degrading, such as snow at or near 0° C., or melting snow or ice resulting in water accumulation on the on the outer end 401 of the radome assembly 305 was found to significantly degrade the RF signal power.

As described above, to mitigate signal attenuation due to the lingering presence of droplets of rain, the outer layer 315 (and the radome body portion 402) may be spaced a predetermined distance from the antenna aperture 208. In accordance with embodiments of the present disclosure, the radome spacer portion 404 provides a suitable thickness to space the outer layer 315 (and potentially the radome body portion 402) a predetermined distance from the upper patch layer of the antenna aperture 208. As described above, in one embodiment of the present disclosure, the outer layer 315 is equidistantly spaced from the upper patch antenna element of each individual antenna element in the antenna aperture at a distance of at least 3.0 mm.

For moisture mitigation and to aid in the run-off of water or moisture accumulating on the radome assembly 305, the outer layer 315 may include a hydrophobic or superhydrophobic material having low surface energy to cause water to bead up and not spread out.

In addition to a hydrophobic or superhydrophobic outer layer 315, tilting of the antenna apparatus 200 (see FIG. 2A) may help to mitigate snow and moisture accumulation.

The thin sheet is then activated on one surface for bonding with an adhesive, such as a pressure sensitive adhesive. Suitable activation may include sodium etching, plasma treatment, corona treatment, or other suitable activation treatments to create bonding sites. The fluoropolymer and adhesive lay-up can be routed into a desired shape. In some embodiments, the outer layer 315 may be formed to include a UV blocker, which may protect the adhesive (e.g., the pressure sensitive adhesive). In some embodiments, the radome body assembly 310 may include a UV blocker in the form of pigmentation.

In some embodiments, the outer layer 315 may be formed by melting the material and adding it to the radome body assembly 310, may be molded (e.g., insert molding), painted, sprayed, and the like.

When formed separately, the outer layer 315 may be coupled to the radome body assembly 310 using any known technique. For example, as discussed above, the outer layer 315 may be bonded to the radome body assembly 310 using an adhesive. The adhesive may include any adhesive such as a pressure sensitive adhesive (PSA) applied to a surface of the outer layer 315. In that regard, the PSA may be placed in contact with the outer layer 315 and the radome body portion 402 and pressure may be applied to the outer layer 315 to couple the outer layer 315 to the radome body assembly 310. In some embodiments, the adhesive may include an epoxy, heat activated adhesive, or any other adhesive in the art.

In some embodiments, the outer layer 315 may be formed to have greater dimensions (e.g., length and width) than those of the radome body portion 402. In such embodiments, the outer layer 315 may be applied to the radome body portion 402 and then cut (e.g., die cut) to have the same dimensions as the radome body portion 402.

In some embodiments, the outer layer 315 may be applied to the radome body assembly 310 using a spray or roll-on technique (e.g., by spraying or rolling on a liquid or gaseous phase of the outer layer material). In some embodiments, a melted fluoropolymer may be applied to the radome body assembly 310 and allowed to dry-harden in place.

In some embodiments, the outer layer 315 may have a thickness 416 that is less than or equal to 20 mil (0.51 mm), less than or equal to 10 mil (0.25 mm), less than or equal to 5 mil (0.13 mm), less than or equal to 3 mil (0.076 mm), less than or equal to 1 mil (0.025 mm), or the like.

Antenna Layers

FIG. 3B illustrates an exemplary antenna apparatus 200 with an exemplary antenna stack assembly 250 in the form of a plurality or stack of layers. The illustrated plurality of layers includes layers of spacers or spacer portions positioned against other layers including antenna layers or layers including antenna elements or components, which may be for instance electronic layers, such as printed circuit board (PCB) layers.

In the illustrated embodiment of FIG. 3B, the layers in the antenna stack assembly 250 layup include a radome assembly 305, a patch antenna assembly 334, a dielectric layer 375, and a printed circuit board (PCB) assembly 380.

As illustrated in FIG. 3B, an outer top layer of the antenna stack assembly 250 includes an outer layer 315 of the radome assembly 305. As described above, in the illustrated embodiment, the radome assembly 305 is a radome assembly including a radome body assembly 310 and an outer layer 305.

In the illustrated embodiment of FIG. 3B, a patch antenna assembly 334 is a phased array antenna assembly made up from a plurality of individual patch antenna elements 304 (see FIGS. 7A and 7B) configured in an array 308 (see FIG. 6A for a top view of an array of upper patch antenna elements 330a). A patch antenna is generally a low profile antenna that can be mounted on a flat surface, including a first flat sheet (or “first patch”) of metal mounted over, but spaced from, a second flat sheet (or “second patch”) of metal, the second patch defining a ground plane. The two metal patches together form a resonant structure. The individual patches may be formed using known metal deposition techniques on a standard PCB layer or other suitable substrate. In an alternate embodiment, the patches may be printed, for example, using a conductive ink, on the patch layers. An array of multiple patch antennas on the same substrate can be used to make a high gain array antenna or phased array antenna for which the antenna beam can be electronically steered.

FIG. 7A illustrates a perspective view of a simplified exemplary individual antenna element 304 including an upper patch antenna element 330a, a lower patch antenna element 370a, and spacing therebetween. The individual element shown FIG. 7A is one of a plurality of antenna elements forming an array of antenna elements (see FIG. 6A).

In the illustrated embodiment, the array 308 of individual patch antenna elements 304 is formed from a plurality of patch antenna layers, including the upper patch antenna layer 330 (see also FIG. 6A), the antenna spacer 335 (see FIGS. 6B and 6C), and the lower patch antenna layer (or ground plane) 370 (see FIG. 6D). As mentioned above, the upper antenna patch layer 330 and the lower patch antenna layer 370 may be formed on standard PCB layers or other suitable substrates. The two layers 330 and 370 are suitably spaced from each other specific by the antenna spacer 335 to achieve the desired tuning of the patch antenna assembly 334. While a two-patch (upper and lower patch) antenna is illustrated herein, other single or multilayer patch antennas may be employed in accordance with embodiments of the present disclosure.

As seen in FIG. 3B, below the radome assembly 305 is positioned adjacent the upper patch layer 330 to protect the upper surface of the upper patch layer 330. FIG. 6A illustrates a top view of the upper patch layer 330. As seen in FIG. 6A, the upper surface of the upper patch antenna layer 330 includes an interior portion 347 having a plurality of individual upper antenna patch elements 330a that make up the upper patches of individual antenna elements 304 defining the antenna array 308. The upper antenna patch elements 330a may be a plurality of discrete individual dots, circles, modified circles, or other polygonal shapes made up of a conductive metal such as copper. The upper antenna patch elements 330a may be separated from each other on the upper patch layer 330 by non-conductive portions of the upper patch antenna layer 330 between the upper antenna patch elements 330a.

The upper patch antenna layer 330 further includes an exterior portion 349 extending to its perimeter. The exterior portion 349 may be relatively small (i.e., may include a relatively small fraction of the entire surface area of the upper patch antenna layer 330 such as 1 percent, 3 percent, 5 percent, 10 percent, or the like), or may fail to exist. The exterior portion 329 may port or flow thermal energy (heat) radially from the overall antenna stack assembly 250 outward to the perimeter of the upper patch layer 330 and to the perimeter of the radome assembly 305. The upper patch layer 330 may define ports 332 through which the elongated members 400 of the radome body assembly 310 (see FIG. 5) may pass. The ports 332 may be located between upper patch antenna elements 330a so as to not interfere with any antenna elements of the antenna array. The ports 332 may be formed during molding or other formation of the upper patch antenna layer 330, may be cut or drilled into a pre-formed upper patch antenna layer 330, or the like. The elongated members 400 of the radome body assembly 310 engage the PCB assembly 380 (see FIG. 10). The upper patch antenna layer 330 may also port or flow heat to the ports 332 where the elongated members 400 port the heat to the radome body assembly 310, which can be used to not only dissipate unwanted heat from electrical components attached to the PCB assembly 380, but also such heat can be repurposed to mitigate snow and rain accumulation on the outer layer 315 of the radome assembly 305.

In some embodiments, the upper patch antenna layer 330 is a PCB substrate having a plurality of upper antenna patch elements 330a. The features of the upper patch antenna layer 330 may be formed by suitable semiconductor processing to obtain the desired feature patterns and shapes.

Turning to FIGS. 3B and 6B, the lower patch antenna layer 370 may be spaced from the upper patch antenna layer 330 by an antenna spacer 335. The antenna spacer 335 may include a plurality of cell walls 336 that define a plurality of open cells 337. The antenna spacer 335 may also define a plurality of ports 331a extending therethrough. The ports 331a may be aligned with ports defined by other layers of the antenna stack 250 and with the elongated members 400 of the radome body assembly 310. In that regard, the elongated members 400 may extend through the ports 331 to couple the layers of the antenna stack 250 together (see FIG. 10). Because the antenna spacer 335 includes only cell walls 336 in an interior portion of the antenna spacer 335, ports 331b may be defined at junctions of cell walls 336. That is, certain cell walls 336 may not intersect with adjacent cell walls to form the ports 331b. The ports 331a and 331b may be formed during molding or other formation process of the antenna spacer 335, may be cut or drilled into a pre-formed antenna spacer 335, or the like.

Each of the plurality of cell walls 336 may extend substantially parallel to a stacking axis of the antenna stack assembly 250. The cells 337 may have a similar shape as the cells 315 defined by the cell walls 316 of the radome spacer portion 404. In some embodiments, the cells 337 may have a different shape such as circular, oval, square, or any other shape. Each of the cells may align with an antenna element 304. The cells 337 may each define a vertical pathway 338 extending along an entire thickness of the antenna spacer 335. That is, the pathway 338 may include a void extending through from a first side to a second side of the antenna spacer 335 such that the antenna spacer 335 lacks any material directly aligned with the antenna elements 304 along the stacking axis.

A group of cell walls 336 and a single pathway 338 within the plurality of cell walls may together form a cell 337. In that regard, each cell 337 may include 6 cell walls 336 and a single pathway 338. In some embodiments, at least a portion of the cell walls 336 may at least partially define an adjacent pathway 338 of an adjacent cell 337. One skilled in the art will realize that the cell walls 336 may have any shape (e.g., rounded, straight, angled, or combinations thereof), and that a cell 337 may include any quantity of cell walls 336 (including a single cell wall 336 defining a single cell), without departing from the scope of the present disclosure.

The cell height of the antenna spacer 335 may be in the range of 1 mm to 2 mm (e.g., about 1.2 mm). Likewise, the cell walls 336 of the antenna spacer 335 may be in the range of 1 mm to 2 mm wide (e.g., about 1.2 mm). Where used in this context, about refers to the referenced value plus or minus 10 percent of the referenced value.

A suitable plastic for the antenna spacer 335 may be thermally conductive and capable of dissipating heat through its structure, while also have a low dielectric constant. In one embodiment of the present disclosure, the antenna spacer 335 may be made from the same or similar materials as the radome body portion 310 and may have a dielectric constant of less than 3.0, and a thermal conductivity value of greater than 0.35 W/m-K or greater than 0.45 W/m-K.

The antenna spacer 335 may be made up of the same or similar materials and by similar manufacturing processes as the radome spacer 310. For example, the antenna spacer 335 may be formed using a polymer with fibers (e.g., fiberglass or carbon fibers) dispersed therein. As seen in FIG. 6B, the antenna spacer 335 may have a honeycomb structure, similar to the radome spacer portion 404 or may be made from a suitable foam or other suitable spacing structure. Although illustrated and described as a single spacing layer, the antenna spacer 335 may be comprised of a plurality of spacer elements defining the space between the upper and lower patch layers 330 and 370 of the patch antenna assembly 334.

Because the antenna spacer 335 may lack a planar surface extending across an entire plane of the antenna spacer 335 (e.g., it may lack an equivalent of the radome body portion 402), any fibers within the polymer used to form the antenna spacer 335 may achieve the desired orientation even though the cell walls 336 are formed continuous with adjacent cell walls 336 (i.e., the honeycomb structure of the antenna spacer 335 may not be nodeless).

When forming the antenna spacer 335, it may be desirable for the fibers to be oriented in such a way as to restrict thermal expansion of the antenna spacer 335. FIG. 6C illustrates one embodiment of the orientation of glass fibers within the antenna spacer 335. As shown, fibers 339 disposed within the cell walls 336 of the antenna spacer 335 extend along a plane defined by the cell wall 336 within which they are disposed. In particular, the glass fibers 339 may extend in a direction that is perpendicular to a plane parallel to the radome body portion 402 of FIG. 5. Such orientation of the glass fibers 339 reduces or restricts thermal expansion of the antenna spacer 335 along the stacking axis.

As will be discussed in further detail below, such fiber orientation within the antenna spacer 335 provides a CTE that is similar to that of the other components of the antenna stack 250 such that any thermal expansion of components of the antenna stack 250 is relatively similar, which allows coupling of some or all components of the antenna stack 250 without adhesive (e.g., as discussed further below, such coupling may be achieved using the elongated members 400). This provides various benefits and advantages such as allowing for relatively easy replacement of various components, reduced part count, reduced cost of manufacture, and the like.

In both the radome body assembly 310 and the antenna spacer 335, it may be sufficient for the fibers to extend along in any direction so long as they are substantially extended (as opposed to knotted, balled up, or the like). For example, it may be desirable for at least a portion (e.g., 25 percent, 50 percent, 75 percent, 90 percent, or the like) of the fibers 339 to extend to a distance that is within 25 percent, 50 percent, 75 percent, 90 percent, or the like of a total possible distance achievable by the fibers without forces acting thereupon. For example, if a fiber can rest at a length of 1 inch, it may be desirable for the fiber to extend to a distance of at least 0.25 inches, 0.5 inches, 0.75 inches, 0.90 inches, or the like within a wall 336 of the antenna spacer 335. This orientation of the fibers thus resists expansion of the planar portions of the cell walls and other planar surfaces. The above-discussed orientations of the fibers results in the total CTE of the entire radome body assembly 310 and antenna spacer 335 being within the desirable values discussed above.

In some embodiments, the antenna spacer 335 may be formed using a nodeless configuration in a similar manner as the radome spacer portion 404. The antenna spacer 335 may be formed using injection molding. In that regard, molten polymer with fibers dispersed therein may be injected into a mold to form the antenna spacer 335. The flow of the polymer/fiber combination through the mold causes the fibers 339 to elongate within the antenna spacer 335, achieving the desired configuration. In particular, the lack of an entire layer-sized planar portion attached to the honeycomb structure of the antenna spacer 335 causes the fibers to elongate while flowing into the cell walls 336.

Referring to FIGS. 3B and 6D, the lower patch antenna layer 370 is spaced beneath the upper patch antenna layer 330. As shown, a top surface 372 of the lower patch antenna layer 370 includes a plurality of individual upper antenna patch elements 370a that make up the lower patches of individual antenna elements 304 defining the antenna array 308. Like the upper antenna patch elements 330a, the lower antenna patch elements 370a may be a plurality of discrete individual dots, circles, modified circles, or other polygonal shapes made up of a conductive metal such as copper. The lower antenna patch elements 370a may be separated from each other on the lower patch layer 370 by portions of the lower patch antenna layer 370 between the lower antenna patch elements 370a. In one embodiment, the lower patch antenna layer 370, like the upper patch antenna layer 330, is a PCB substrate having a plurality of upper antenna patch elements 370a.

The lower patch antenna layer 370 may also define ports 333 extending from the top surface 372 to a bottom surface 373. As with ports defined by other layers of the antenna stack 250, the elongated members 400 of the radome body assembly 310 may extend through the ports to couple the layers together (see FIG. 10). The ports 333 may be located between lower patch antenna elements 370a such that the elongated members 400 fail to interfere with operation of the various lower patch antenna elements. The ports 333 may be formed with the lower patch antenna layer 370 during molding or other formation of the lower patch antenna layer 370, may be cut or drilled into a pre-formed lower patch antenna layer 370, or the like.

As seen in FIGS. 7A, the individual lower patch layer elements 370a are configured to align with the individual upper patch antenna elements 330a, for example, in a vertical stack. The lower patch antenna elements 370a may be the same as or similar in shape and configuration as the upper patch antenna elements 330a. In the illustrated embodiment, the upper patch elements 330a are generally circular in configuration and include a plurality of slots for antenna polarization or tuning effects, while the lower patch antenna elements 370a are generally circular in configuration.

As seen in FIG. 7B, the upper patch antenna layer 330 is spaced by an antenna spacer 335 from the lower patch antenna layer 370. As described above, the antenna spacer 335 may be made up of the same or similar material as the radome spacer portion 404 (and, thus, may include the same material as the entire radome body assembly 310), and may also have a cell and wall structure similar to that of the radome spacer portion 404. Similar to the upper patch antenna elements 330a and the radome spacer portion 404, each of the plurality of apertures in the antenna spacer 335 may include a vertical pathway to align with each lower patch element 370a (at the bottom) and each upper patch antenna element 330a (at the top) to define a plurality of individual antenna elements 304 in the antenna array 308.

Below the upper and lower antenna patch elements 330a and 370a is the PCB assembly 380, which includes circuitry that may be aligned with the upper and lower antenna patch elements 330a and 370a, which together may form a resonant antenna structure. The PCB assembly 380 is separated from the lower patch antenna 370 by a dielectric spacer 375.

Dielectric Spacer

Referring to FIGS. 3B, 8A, and 8B, a dielectric layer 375 provides an electrical insulator between the patch antenna assembly 334 and the PCB assembly 380 and spaces the patch antenna assembly 334 from the PCB assembly 380. The dielectric layer 375 may have a low dielectric constant (which may be referred to as relative permittivity), for instance in the range of about 1 to about 4 at room temperature.

In accordance with embodiments of the present disclosure, in addition to being an electrical insulator, the dielectric spacer 375 may be configured to be a fire enclosure for the antenna apparatus 200. In that regard, the dielectric spacer 375 may be manufactured to have flame retardant properties, for example, by inclusion of 5% decabromodiphenyl ethane (DBDPE) together with the dielectric materials of the dielectric spacer 375.

The dielectric spacer 375 may include a planar body formed from a dielectric material 500 with a plurality of holes 502 formed therethrough. The material 500 of the dielectric spacer 375 may include any dielectric material. For example, the dielectric spacer 375 may include a polymer, silicon, or any other material or materials. In some embodiments, the dielectric spacer 375 may include fibers dispersed therein. The fibers may be used to reduce the CTE value of the dielectric spacer to match the CTE of the additional layers of the antenna stack 250.

Exemplary materials which may be used as the material 500 of the dielectric spacer 375 include polypropylene (PP), polycarbonates, polybutylene terephthalate (PBT), polyphenylene ether (PPE), poly(p-phenylene oxide) (PPO), polystyrene (PS), polyethylene terephthalate (PET), polyvinyl chlorine (PVC), liquid crystal polymer (LCP), other polymers, or mixtures thereof. Polyethylene, such as linear low density polyethylene (LLDPE), high density polyethylene (HDPE) may also be employed, however, they may be modified to have reduced CTE.

In some embodiments, the material 500 may include a blend between PPO and PP, a blend between PPO and PPE, or the like. In some embodiments, the blended material may have fibers dispersed therethrough. The blend may include any percentage of PPO (such as 5 percent, 20 percent, 50 percent, 70 percent, 95 percent, or the like) and any percentage of PP or PPE (such as 5 percent, 20 percent, 50 percent, 70 percent, 95 percent, or the like). In some embodiments, optimal characteristics (e.g., CTE, dielectric constant, or the like) may be achieved by using a blend that is between 10 percent and 50 percent PPO and between 50 and 90 percent PP or PPE.

The holes 502 formed in the dielectric spacer 375 may optimize a scan angle of the antenna apparatus 200 (because the antenna apparatus 200 is a phased array antenna, it is capable of scanning in multiple directions). For example, the combination of the material 500 and the holes 502 (including the shape, size, and location of the holes 502) may increase a scan angle (i.e., an angle at which a main beam may form relative to the stacking axis of the antenna stack 250) by at least 0.5 percent, by at least 1 percent, by at least 1.5 percent, by at least 2 percent, by at least 2.5 percent, by at least 3 percent, or the like. In experiments, the dielectric spacer 375 shown herein achieved improvements in scan angle of at least 2 percent.

The holes 502 may have any shape. For example, the holes 502 may be circular, oval, triangular, square, rectangular, or any other polygonal or other shape. The holes 502 may have a diameter 504. In some embodiments, the diameter 504 may be between 1 millimeter and 25 millimeters (40 mil and 984 mil), between 2 millimeters and 15 millimeters (80 mil and 591 mil), between 3 millimeters and 10 millimeters (120 mil and 400 mil), or about 5 millimeters (197 mil). Where used in this context, “about” refers to the referenced value plus or minus 10 percent of the referenced value.

In some embodiments, the holes 502 may be located around an individual antenna element 304 (i.e., around an individual upper patch antenna element 330a and lower patch antenna element 370a). That is, a group of holes 508 in the material 500 of the dielectric spacer 375 may encircle or surround a portion 510 of solid dielectric material 500. The holes 502 may surround portions 510 such that each portion 510 aligns with a different antenna element 304 such that solid dielectric material 500 is aligned with each antenna element 304 along the stacking axis (shown in detail in FIG. 8B). In some embodiments, the holes 502 may align with the gaps 453 between adjacent cell walls 316 of the radome spacer portion 404. This orientation of holes 502 aids in achieving the desired properties of the dielectric spacer 375 (i.e., the CTE value, the dielectric value and properties, the scan angle improvement, and the like).

As shown in FIG. 8B, each of the plurality of antenna elements 304 of the upper patch layer 330 align with each of the plurality of apertures 317 having the cell walls 316 of the radome spacer 310 and with openings of cells 337 defined by the antenna spacer 335. For example, each of the antenna elements 304 are disposed within the apertures 317 and the cells 337 of the antenna spacer 335 to provide suitable spacing around each of the antenna elements 304.

At least some of the holes 502 of the dielectric spacer 375 may align with the ports 331, 332, 333 of the upper patch antenna layer 330, the antenna spacer 335, and the lower patch antenna layer 370. In that regard, the elongated members 400 may extend through the at least one of each port 331, 332, 333 and at least one hole 502 to couple the layers of the antenna stack 250 together.

The material 500 of the dielectric layer 375 may have a thickness 506. The thickness 506 may be, for example, between 0.1 mm and 5 mm (3.9 mil and 197 mil), between 0.2 mm and 2 mm (7.9 mil and 79 mil), between 0.5 mm and 1 mm (20 mil and 39 mil), or about 0.7 mm (28 mil). These thicknesses 506 may aid in achieving the desired properties of the dielectric spacer 375.

Some selected polymers may inherently have a CTE within the aforementioned ranges (such as LCP) or may be modified to have such a CTE by impregnating with fiber fillers (e.g., fiberglass) to cause the CTE to fall within these ranges. Accordingly, the aforementioned polymers and other suitable polymers may be modified to reduce the CTE by the addition of other components, such as glass fiber. Given that the glass fiber may have a CTE lower than the polymer in which it is impregnated, it serves to restrain and lower the CTE of the polymer (i.e., the fibers expand at a significantly reduced rate relative to the polymer and, thus, restrict expansion of the polymer in response to heating the layer). Particular exemplary fiberglass modified polymers includes glass filled PP, glass filled polycarbonate, or a glass filled PPE/PP polymer blend, glass filled PPO, glass filled PBT, as well as other fiberglass- or other fiber-modified polymers. For example, other suitable fibers may include carbon fibers, aramid fibers, boron fibers, polyethylene fibers, Poly p-phenylene-2,6-benzobisoxazole (PBO) fibers, quartz fibers, ceramic fibers, basalt fibers, hybrid fibers, natural fibers (e.g., abaca, bamboo, coconut, flax, hemp, jute, kenaf, sisal, and the like), and the like.

In some embodiments, the dielectric spacer 375 may include any other shape of holes so long as material 500 is aligned with the antenna elements 304. In some embodiments, the dielectric spacer 375 may lack holes or openings. In some embodiments, holes or openings may be aligned with the antenna elements 330a, 370a along the stacking axis. In some embodiments, the dielectric spacer 375 may include pucks, disks, or other separated pieces of dielectric material that is aligned with the individual antenna elements 304. In some embodiments, a plurality of pucks, disks, or other pieces of dielectric material may be coupled together, e.g., via wires, strips of material, or the like, to form the dielectric spacer 375. The advantageous features of the dielectric spacer 375 may be achieved by using a dielectric material (e.g., of the composition described above) aligned with the individual antenna elements 304 along the stacking axis; and voids, or a lack of dielectric material, at other locations on the same plane as the dielectric material.

The combination of materials described above forming the dielectric material 500 along with the holes 502 (including the shape, size, and location thereof) may together achieve a desirable set of characteristics or parameters of the dielectric spacer 375. In particular, the combination of materials used and holes 502 may provide a desirable CTE and a desirable dielectric constant which may be unavailable for commercial purpose. At least one of the CTE values and dielectric values allow the dielectric spacer 375 to achieve desirable beamforming capabilities and steering of the antenna apparatus 200, as well as a desirable signal-to-noise (SNR) ratio for received signals. For example this combination may provide a layer having a dielectric constant of between 1 and 5, between 2 and 4, between 2.5 and 3.5, or about 2.8; and a CTE of between 10 and 30, between 15 and 25, between 17 and 23, or about 20. In an exemplary embodiment, the dielectric spacer 375 may have a dielectric constant of about 2.8 and a CTE of about 20. Where used in this context, the term “about” refers to the referenced value plus or minus 10 percent of the referenced value. As referenced above, materials are unavailable for commercial purpose with these properties.

PCB Assembly

In some embodiments and as shown in FIG. 3B, the patch antenna assembly 334 may be mechanically and electrically supported by a printed circuit board (PCB) assembly 380. The PCB assembly 380 is generally configured to connect electronic components using conductive tracks, pads and other features etched from one or more sheet layers of copper laminated onto and/or between sheet layers of a non-conductive substrate. The PCB assembly 380 may be a single or multilayer assembly with various layers including copper, laminate, substrates, and the like, and may have various circuits formed therein.

In typical PCB construction, individual PCB layers are typically made up of fiberglass material surrounding a pattern of copper traces defining electrical connections. The copper and fiberglass having similar CTE values and generally have no purposeful air gaps within the structure. Therefore, the various layers defining a multi-layer PCB can be laminated together under high heat and pressure conditions. Likewise, the CTE value of the PCB assembly 380 may be relatively similar to the CTE of the first and second antenna patch layers 330 and 370, and, by design, to the other plastic spacer layers 310 and 335 of the antenna stack assembly 250.

Referring to FIGS. 3B, 8B, 9A, 9B, and 9C, the PCB assembly 380 may have a first side 383 that faces and contacts the dielectric spacer 375 and a second side 384 opposite the first side 383. The PCB assembly 380 may include a plurality of electronic components 382 coupled thereto, such as microchips, processors, signal processors, beamforming logic devices, power modules, GPS receivers, resistors, capacitors, inductors, transistors, memory devices, and the like. Because the first side 383 faces the dielectric spacer 375 and the electronic components 382 may extend away from the PCB assembly 380, it may be undesirable for such electronic components 382 to be located on the second side 384 of the PCB assembly 380. Due to the lack of electronic components on the first side 383 extending away from the first side 383, the first side 383 may be in contact with and lie flush with the dielectric spacer 375. Additional electronic components (such as signal traces or other logic devices) may be located within the layers of the PCB assembly 380 so long as they avoid extending outward from the first side 383. In that regard, thermal energy generated by, or dispersed by, the PCB assembly 380 may travel away from the PCB assembly 380 to the dielectric spacer 375.

The PCB assembly 380 may define or include a plurality of ports 381 extending through the first side 383 and the second side 384. The ports 381 may be aligned with the ports 331, 332, 333 of the antenna layers and some holes 502 of the dielectric spacer 375. In that regard, the elongated members 400 of the radome assembly 305 may extend through the ports 381 of the PCB assembly to couple the radome assembly 305 to the PCB assembly 380 and, thus, coupling the layers of the antenna stack assembly 250 together (see FIG. 10).

CTE Matching

In some antenna assemblies in the art, there may be large power requirements and/or the heat generated by the internal components or the PCB assembly are such that heat dissipation by spacer layers is required. Such spacer layers are therefore selected to have high thermal conductivity to assist with dispersing heat, as well as a low dielectric constant to provide higher scan angle capabilities in phased array by shortening the electrical distance between adjacent elements. However, such materials usually also have an associated high CTE, and in particular higher than that of the PCB assembly 380 and the similarly constructed antenna layers 330 and 370 (all described herein as PCB assemblies). For instance, materials such as linear low-density polyethylene (LLDPE) have high thermal conductivity with a low dielectric constant but have the associated property of high CTE, and in particular a CTE that is notably higher than that of the PCB assemblies. As a result, such materials (i.e., spacer layers) may be bonded via adhesive to the PCB assemblies or other layers so as to avoid the shifting of layers that may be associated with spacer layers expanding and contracting at differing degrees than the PCB assemblies and which may have a detrimental impact on antenna element tuning.

Referring to FIGS. 3B, 4B, and 6B and in some embodiments there may be reduced power requirements and/or the heat generated by the PCB assembly 380 or other components in the antenna stack assembly 300 may be reduced, or there may be otherwise improved heat mitigation or dissipation from the assembly. Accordingly, in some embodiments there can be a reduced requirement for spacer layers, such as the radome spacer portion 404 and the antenna spacer 335, within the antenna stack assembly 300 to have high thermal conductivity to assist in heat dissipation. As a result, with the reduced need for materials with high thermal conductivity, materials for spacers can be selected for, or modified to have, a relatively low CTE. These spacer layers may be selected so as to expand and contract to the same or similar degree, or to a lesser degree, than the PCB assembly 380 and antenna layers 330, 370 (which may be formed from a similar material having a similar CTE as the PCB assembly 380). Likewise, the dielectric layer 375 may be selected from a material having a CTE that is similar to that of the PCB assembly 380 and antenna layers 330, 370, or may be modified to have the similar CTE. An improved CTE match with the PCB assembly 380 and antenna layers 330, 370 provides a reduced variety of materials to select from, but also eliminates the need to bond the layers together via adhesive. Such use of adhesive resists relative expansion of adjacent layers and, thus, resists deformation of each antenna element and connections between layers. However, use of the adhesive increases manufacturing difficulty and manufacturing cost of the antenna assembly, and makes repairing each layer difficult.

The present disclosure provides systems and methods that cause each layer of the antenna assembly 250 to have a relatively similar CTE which results in use of adhesives being optional. In particular, the CTE matching achieved in the present design is at least partially achieved by selecting base materials for certain layers (e.g., the radome body assembly 310, the antenna spacer 335, and the dielectric layer 375) and impregnating such layers with fibers (e.g., fiberglass). Tests have confirmed that the CTE of each layer is sufficiently well matched that use of adhesive can be eliminated.

Because the CTE of each layer may be relatively similar, the layers may be retained without using adhesives. In that regard, stakes (e.g., the elongated members 400 of the radome body assembly 310) may be optionally used to couple one or more adjacent layers. In some embodiments, other layers of the antenna stack assembly 250 may have similar stakes or elongated members (e.g., the antenna spacer 335, the PCB assembly 380, or the like) to couple together two or more layers. In some embodiments, multiple layers may have elongated members such that each layer is only coupled to one or more layer with the elongated members. In some embodiments, the radome may be curved to preload the layers against the PCB assembly. In some embodiments, fasteners (e.g., clips, screws, bolts, rivets, snap-fit connectors, or the like) may be used to couple two ore more layers together. Some embodiments may utilize any combination of elongated members of existing layers, fasteners, adhesives, and preloading of one or more layer.

Accordingly, in some embodiments disclosed herein, at least one of the antenna spacer 335, the radome body assembly 310 (including at least one of the radome body portion 402 and the radome spacer portion 404), and the dielectric layer 375 is configured to have a coefficient of thermal expansion CTE that is about the same as or less than the PCB assembly 380, or alternatively, to have a CTE that is no more than three times the CTE of the PCB assembly 380, or alternatively, no more than two times the CTE of the PCB assembly 380. That is, the polymer of the at least one of the antenna spacer 335, the radome body assembly 310, and the dielectric layer 375 may have a CTE that is significantly greater than (or less than) that of the PCB assembly 380 but may be impregnated or formed with fibers therein such that the combined CTE of the polymer and fibers of the at least one of the antenna spacer 335, the radome body assembly 310, and the dielectric layer 375 has a CTE that falls within the specified ranges of the CTE of the PCB assembly. In some embodiments, the patch antenna layers 330, 370 may have a CTE that is about the same as or less than, no more than three times, no more than two times, or the like, the CTE of the PCB assembly 380. In some embodiments, the patch antenna layers 330 may be formed using similar materials as the PCB assembly 380 and may thus have similar CTE values as the PCB assembly 380. In such embodiments, the CTE of the antenna spacer 335, the radome body portion 310, and the dielectric layer 375 may have a similar relationship to the CTE of the patch antenna layers 330, 370 as to the CTE of the antenna PCB assembly 380.

The PCB assembly 380 (as well as at least one of the upper patch antenna layer 330, the lower patch antenna layer 370, and the dielectric layer 375) may have a CTE of about 14 parts per million per degree Celsius (ppm/° C.), and/or may range from about 14 to 17 ppm/° C. Accordingly, the radome body portion 310 and/or antenna spacer 335 (and/or the dielectric layer 375) may have a CTE of about 45 ppm/° C. or less, alternatively about 34 ppm/° C. or less, alternatively about 17 ppm/° C. or less, alternatively about 14 ppm/° C. or less. In some embodiments, the CTE of at least one of the radome body portion 310, the antenna spacer 335, and the dielectric layer 375 may range from about 0.1 ppm/° C. to about 45 ppm/° C., alternatively from about 0.1 ppm/° C. to about 34 ppm/° C., or alternatively from about 0.1 ppm/° C. to about 17 ppm/° C.

In some embodiments, some or all layers of the antenna stack assembly 250 may have differing CTEs; however, in such embodiments, a layer having the greatest CTE (e.g., the lower patch antenna layer 370) may have a CTE that is no more than 3 times the CTE as a layer having the lowest CTE (e.g., the PCB assembly 380). Alternatively, a layer having the greatest CTE may have a CTE that is no more than 2 times the CTE as a layer having the lowest CTE or, alternatively, may have a CTE that is no more than 1.5 times the CTE as a layer having the lowest CTE or, alternatively, about the same as the layer having the lowest CTE. Where used in this context, about refers to the referenced value plus or minus 10 percent of the referenced value.

Further, as power generation by the various elements of the antenna stack is relatively low, the elements of the antenna stack 250 may be permitted to have relatively low thermal conductivity. In that regard, at least one of the radome body assembly 310 and the antenna spacer 335 may have a thermal conductivity value of less than 0.5 watts per meter-kelvin (W/m-K), alternatively less than 0.35 W/m-K, alternatively less than 0.25 W/m-K, alternatively less than 0.2 W/M-K, or the like.

Exemplary materials which may be used as the radome spacer 310 and/or antenna spacer 335 include polypropylene (PP), polycarbonates, polybutylene terephthalate (PBT), polyphenylene ether (PPE), poly(p-phenylene oxide) (PPO), polystyrene (PS), polyethylene terephthalate (PET), polyvinyl chlorine (PVC), liquid crystal polymer (LCP), other polymers, or mixtures thereof. Polyethylene, such as linear low density polyethylene (LLDPE), high density polyethylene (HDPE) may also be employed, however, they may be modified to have reduced CTE.

Some selected polymers may inherently have a CTE within the aforementioned ranges (such as LCP) or may be modified to have such a CTE by impregnating with fiber fillers (e.g., fiberglass) to cause the CTE to fall within these ranges. Accordingly, the aforementioned polymers and other suitable polymers may be modified reduce the CTE by the addition of other components, such as glass fiber. Given that the glass fiber may have a CTE lower than the polymer in which it is impregnated, it serves to restrain and lower the CTE of the polymer (i.e., the fibers expand at a significantly reduced rate relative to the polymer and, thus, restrict expansion of the polymer in response to heating the layer). Particular exemplary fiberglass modified polymers includes glass filled PP, glass filled polycarbonate, or a glass filled PPE/PP polymer blend, glass filled PPO, glass filled PBT, as well as other fiberglass- or other fiber-modified polymers. For example, other suitable fibers may include carbon fibers, aramid fibers, boron fibers, polyethylene fibers, Poly p-phenylene-2,6-benzobisoxazole (PBO) fibers, quartz fibers, ceramic fibers, basalt fibers, hybrid fibers, natural fibers (e.g., abaca, bamboo, coconut, flax, hemp, jute, kenaf, sisal, and the like), and the like.

When forming the structure of the radome body assembly 310 and the antenna spacer 335, the fibers may be oriented in such a way so as to restrict or otherwise adjust thermal expansion of the respective layer. In particular and referring to FIG. 4C, due to the radome body portion 310 having the planar radome body portion 402 and the celled radome spacer portion 404, it is desirable for the plurality of fibers 454 in the radome body portion 402 to extend along the plane defined by the radome body portion 402 (i.e., extend in directions that are parallel to the plane) to resist outward expansion of the radome body portion 402 (e.g., to resist increasing a size of the length and width of the radome body portion 402). It is likewise desirable for the plurality of fibers 455 in the radome spacer portion 404 to extend along a plane that is perpendicular to the plane defined by the radome body portion 402 (e.g., to extend away from the radome body portion 402, for example, in a direction perpendicular to the plane of the radome body portion 402) to resist expansion of the radome spacer portion 404 in a direction perpendicular to the plane of the radome body portion 402 (i.e., to resist expansion of the radome spacer portion 404 outward from the radome body portion 402). In some embodiments, it is desirable for the plurality of fibers 455 in the radome spacer portion 404 to extend along a plane defined by the walls 316 of the radome spacer portion 404 (i.e., to resist planar expansion of the walls 316 of the radome spacer portion 404).

In some embodiments, it is sufficient for the fibers 455 in the radome spacer portion 404 to extend along the plane of the walls 316 in any direction so long as they are substantially extended (as opposed to knotted, balled up, or the like). For example, it may be desirable for at least a portion (e.g., 25 percent, 50 percent, 75 percent, 90 percent, or the like) of the fibers 455 to extend to a distance that is within 25 percent, 50 percent, 75 percent, 90 percent, or the like of a total possible distance achievable by the fibers 455 without forces acting thereupon (i.e., within a certain percentage of a total length of the fibers). For example, if a fiber can rest at a length of 1 inch, it may be desirable for the fiber to extend to a distance of at least 0.25 inches, 0.5 inches, 0.75 inches, 0.90 inches, or the like within a wall of the radome spacer portion 404. Likewise, it may be sufficient for the fibers 454 in the radome body portion 402 to extend along the plane of the radome body portion 402 in any direction so long as they are substantially extended (as opposed to knotted, balled up, or the like). For example, it may be desirable for at least a portion (e.g., 25 percent, 50 percent, 75 percent, 90 percent, or the like) of the fibers 454 to extend to a distance that is within 25 percent, 50 percent, 75 percent, 90 percent, or the like of a total possible distance achievable by the fibers 454 without forces acting thereupon. For example, if a fiber can rest at a length of 1 inch, it may be desirable for the fiber to extend to a distance of at least 0.25 inches, 0.5 inches, 0.75 inches, 0.90 inches, or the like within the plane of the radome body portion 402.

This orientation of the fibers 454, 455 thus resists expansion of the planar portions of the radome body portion 310. The above-discussed orientations of the fibers results in the total CTE of the entire radome body assembly 310 (including the radome body portion 402 and the radome spacer portion 404) being within the desirable values discussed above. As referenced above, this specific orientation of the fibers 454, 455 may be achieved by spacing the cell walls 316 of the radome spacer portion 404 apart, as shown in FIG. 4C (i.e., by making the cells of the radome spacer portion 404 nodeless). The radome body assembly 310 may be formed using injection molding. In that regard, molten polymer with fibers dispersed therein may be injected into the radome body portion 402. The flow of the polymer/fiber combination through the radome body portion 402 and the radome spacer portion 404 causes the fibers 454, 455 to elongate within the respective portions 402, 404, achieving the desired configuration. In particular, the nodeless configuration of the cell walls 316 causes the fibers to elongate while flowing into the cell walls 316. Experiments were performed by injection molding molten polymer/fibers into a mold that includes a planar portion (similar to the radome body portion 402) and a honeycomb portion extending therefrom in which all cell walls were connected. In such experiments, the fibers within the cell walls bunched up together and failed to extend to a desirable length and, thus, the resulting structure lacked the desirable CTE values.

In some embodiments, this desirable orientation of the fibers may be achieved in other manners such as by forming the radome body portion 402 and the radome spacer portion 404 separately, by using a different manufacturing method than injection molding, by manufacturing a fiber mesh and then injecting or otherwise adding the polymer to the pre-formed mesh, or the like. In some embodiments, the CTE of the radome body assembly 310 may be caused to be in the range discussed above in different manners such as, for example, by using different polymer materials and allowing the fibers in the cell walls to orient parallel to the plane defined by the radome body portion 402.

In some embodiments, the antenna spacer 335 may lack a planar section (such as the radome body portion 402). The antenna spacer 335 may also include a polymer with fibers dispersed therein. Because the antenna spacer lacks a planar section, the fibers may elongate in the cell walls even if the cell walls are all connected together. As with the radome spacer portion 404, it may be desirable for the fibers to extend along a plane defined by the walls of the structure. That is, it is desirable for the fibers to extend in a direction that is substantially parallel to the plane formed by each wall of the structure of the antenna spacer. Similarly, it may be desirable for at least a portion (e.g., 25 percent, 50 percent, 75 percent, 90 percent, or the like) of the fibers in the antenna spacer 335 to extend to a distance that is within 25 percent, 50 percent, 75 percent, 90 percent, or the like of a total possible distance achievable by the fibers without forces acting thereupon. For example, if a fiber can rest at a length of 1 inch, it may be desirable for the fiber to extend to a distance of at least 0.25 inches, 0.5 inches, 0.75 inches, 0.90 inches, or the like within the plane of the walls of the antenna spacer 335.

As with the radome body assembly 310, the antenna spacer 335 may be formed using injection molding. It was found during experimentation that the fibers within the antenna spacer 335 achieved this desirable elongation and orientation with the structure shown in the drawings. Likewise, the CTE of the antenna spacer 335 reached desirable levels with this injection molding process.

As with the radome body portion 310, this desirable orientation of the fibers may be achieved in other manners such as by using a different manufacturing method than injection molding, by manufacturing a fiber mesh and then injecting or otherwise adding the polymer to the pre-formed mesh, or the like. In some embodiments, the CTE of the antenna spacer 335 may be caused to be in the range discussed above in different manners such as, for example, by using different polymer materials and allowing the fibers in the cell walls to orient parallel to the plane defined by the walls of the antenna spacer 335.

The fiber orientation in the radome body assembly 310 and the antenna spacer 335 may result in the respective CTE reaching desirable levels. In some embodiments, the desirable CTE may only be achieved in the direction along which the fibers extend. The fiber orientation likewise results in a relatively low anisotropy in the radome body assembly 310 and the antenna spacer 335.

Further to the above, in assemblies where there is reduced power and/or low heat is generated, the walls of the radome spacer portion 404 and/or the antenna spacer 335 may be thinner than in other assemblies. In assemblies where heat is generated and requires dissipation, the thicker walls assist in heat transfer. However, in embodiments as disclosed herein where there is less heat generated, there are also reduced requirements by the spacers for heat dissipation. Accordingly, cell walls 316 of the radome spacer portion 404 (and cell walls of the antenna spacer 335) may provide a greater proportion of air to mitigate any RF interference with antenna signals from the antenna array 308. In some embodiments, the volumetric percent of solid surface area or the body of at least one of the radome spacer portion 404 and the antenna spacer 335 with the remainder being air is 20% or less, 17% or less, 16% or less, 15% or less, or the like.

Coupling of Antenna Stack Assembly

As referenced above, if the CTE of each layer of the antenna stack assembly 250 is similar (as discussed above; for example, if the layer with the greatest CTE is no greater than 3 times, 2 times, 1.5 times, or the like the layer with the lowest CTE) then the layers of the antenna stack assembly 250 may be coupled together without use of adhesive with minimal negative consequences. To couple the layers of the antenna stack assembly 250 together without using adhesive, mechanical fasteners may be used. In particular and as shown in FIGS. 4B and 10, the radome body assembly 310 may include a plurality of elongated members extending therefrom in a direction away from the radome body portion 402.

Each of the additional layers (beyond the radome body assembly 310) may have openings or apertures that each align in the direction of the stacking axis with at least one of the elongated members 400 in response to each of the layers being aligned for assembly. For example, the upper patch antenna layer 330 defines ports 332, the antenna spacer 335 defines ports 331, the lower patch antenna layer 370 defines ports 333, the dielectric layer 375 defines openings 502, and the PCB assembly 380 defines ports 381. Each of the ports 332, 331, 333, 502, 381 may align vertically, or along the stacking axis, with the elongated member 400. In some embodiments, some or all of the openings may serve multiple purposes. For example, the ports 331 in the antenna spacer 335 may also operate as cell centers (e.g., be surrounded by cell walls of the antenna spacer 335) such that additional openings beyond the cells are unnecessary. Likewise, the holes 502 of the dielectric layer may also operate as the openings formed therein that align with the antenna elements antenna assembly. In some embodiments, at least some ports 331 in the antenna spacer 335 may be formed separate from the cell centers. In some embodiments, at least some holes 502 in the dielectric layer 375 may be formed separate from the other openings of the dielectric layer 375 (e.g., to avoid an elongated member 400 extending through an antenna element). In that regard, the antenna spacer 335 may be designed to facilitate alignment of the ports 331 and the cell centers or to avoid alignment of the ports 331 and the cell centers. Similarly, the dielectric layer 375 may be designed to facilitate alignment of the functional openings and the fastening holes 502 or to avoid alignment of the functional openings and the fastening holes 502.

In order to couple the layers of the antenna stack assembly 250 together, the layers may be stacked in order (e.g., with the radome assembly 305 at one end and the PCB assembly 380 at the other, with the remaining layers stacked in the same configuration shown in FIGS. 3B and 10) in such a manner that the elongated members 400 extend through the openings of the respective layer. In particular, the elongated members 400 may extend through the openings of the layers in the following order (starting from the closest opening to the radome body assembly 310): 332, 331, 333, 502, 381. The elongated members 400 may each include a proximal end at or near the radome body portion 402 and a distal end opposite the proximal end (i.e., the distal end extends away from the radome body portion 402). Stated differently, the proximal end of the elongated members 400 may be coupled to the radome body assembly 310 (such as the radome body portion 402, the radome spacer portion 404, or the like). The distal end of the elongated members 400 may extend through each of the openings 332, 331, 333, 502, 381 and the distal end may be deformed, as discussed further below, to resist removal of the distal end from the openings 332, 331, 333, 502, 381. The layers may be pressed together using any known technique such as manual pressing, mechanical pressing, use of a vice, or the like. In some embodiments, the pressing may continue until the coupling is complete, may only occur until the layers are in the desired configuration, or for any duration therebetween.

While the layers are pressed together and the elongated members 400 extend through the openings, distal ends 470 of the elongated members may be warped or otherwise deformed. For example, the distal ends 470 may be heated, may be heated and reshaped manually or with equipment, may have pressure applied thereto for reshaping, or the like. The distal ends 470 may be manipulated such that a dimension 610 of the distal end 470 in a direction parallel to a plane formed by the PCB assembly 380 is greater than a diameter 612 of the port 381 of the PCB assembly 380. The distal end 470 may be manipulated in such a way that the dimension 610 that is greater than the diameter 612 is at a location adjacent to (i.e., within 1 mil (0.0254 mm), 10 mils (0.254 mm), 100 mils (2.54 mm), 300 mils (7.62 mm), or the like) a plane defined by the PCB assembly 380 while the layers are pressed together.

After hardening of the distal end 470, the elongated members 400 couple the entire antenna stack assembly 250 (see FIG. 3B) from the radome body assembly 310 (due to the monolithic nature thereof) to the PCB assembly (due to the dimension 610 of the distal end 470 being greater than the diameter 612 of the port 381 while the layers are stacked together). Thus, the elongated members 400 may resist separation of the radome body assembly 310 from the remaining layers of the antenna stack assembly in the direction of the stacking axis, and may also resist separation of the PCB assembly 380 from the remaining layers of the antenna stack assembly in the direction of the stacking axis. Because the elongated members 400 also extend through openings of the remaining layers and the remaining layers are sandwiched between the radome body assembly 310 and the PCB assembly, the elongated members 400 also resist separation of any one of the layers from any other of the layers. Furthermore, because the elongated members 400 extend through openings defined by each layer of the antenna stack assembly, the elongated members 400 also resist separation of any layer from any other layer in directions parallel to the plane defined by surfaces of the layers.

Although the outer layer 315 of the radome assembly 305 may not be coupled to the remaining layers via the elongated members, the outer layer 315 may be bonded to the radome body portion 402 using an adhesive (e.g., pressure-sensitive adhesive) or any other mechanism (e.g., other types of bonding such as chemical bonding). Therefore, the adhesive of the outer layer 315 and the interaction between the elongated members 400 and the openings may sufficiently couple each layer of the antenna stack assembly 250 together without use of any additional adhesive. In some embodiments, adhesive, fasteners, or other coupling means may be used to couple two or more layers of the antenna stack assembly 250 together. In some embodiments, additional adhesive may be desirable. For example, in climates with relatively high temperatures (e.g., equatorial locations), thermal expansion may be greater than other locations. In such climates, it may still be desirable to use at least some adhesive between two or more layers of the antenna stack assembly. In some embodiments, the outer layer 315 may be coupled to the radome body portion 402 in any manner in addition to, or instead of, the adhesive. For example, another fastener (e.g., screw, bolt, snap-fit connector, clip, or the like) may be used to fasten or couple the outer layer 315 to the radome body portion.

In some embodiments, the PCB assembly 380 may include electronic components 650 (e.g., semiconductor processors, memory chips, global positioning system (GPS) sensors, or the like) located on, and coupled to, the PCB assembly 380. In some embodiments, the components 650 may be located on a bottom surface (e.g., a surface facing away from the remaining layers of the antenna stack assembly 250) due to potential direct contact between a top surface of the PCB assembly 380 (i.e., opposite the bottom surface) and the dielectric layer 375. In that regard, the components 650 may remain coupled to the antenna stack assembly 250 due to the coupling of the components 650 to the PCB assembly 380.

In some embodiments, some or all of the layers of the antenna stack assembly 250 may be coupled together using any additional or alternative method. In some embodiments, the distal end 470 may be coupled to the PCB assembly in another manner. For example, the distal end 470 may be bonded to the PCB layer (and, potentially, additional layers). As another example, a clip may be positioned on the distal end 470 while it is protruding through the port 381 to resist separation of the distal end 470 and the PCB assembly 380.

In some embodiments, another one or more layer of the antenna stack assembly 250 may include or be coupled to elongated members. For example, the PCB assembly 380 may be formed to have a monolithic elongated member, or an elongated member may be coupled thereto after formation of the PCB assembly 380. The elongated member may extend through at least one additional layer and may have a distal end that is reshaped (or bonded, or a clip coupled thereto) while extending through the other one or more layer to resist separation of the one or more layer and the PCB assembly 380.

In some embodiments, other fasteners may be used to couple two or more layers together in addition to, or instead of, the elongated members. For example, a rivet, bolt, screw, clip, snap-fit connector, or any other fastener may extend through two or more layers of the antenna stack assembly 250 in order to couple the two or more layers together.

In some embodiments, multiple mechanisms may be used to couple the antenna stack assembly 250 together. For example, an elongated member may extend from the radome body assembly 310 through the antenna spacer 335 and be coupled thereto, and rivets may be used to couple the antenna spacer 335 and the PCB assembly 380 together. As another example, a bolt may extend through openings defined by each layer (including the outer layer 315) and may have a head located outside of one opening (e.g., located above the outer layer 315) and be coupled to a nut outside of another opening (e.g., located below the PCB assembly 380) in order to resist separation of each layer relative to the remaining layers. In some embodiments, a fastener may be used to couple one or more layer of the antenna stack assembly 250 to the lower enclosure 204 in addition to, or instead of, the method discussed below.

As will be discussed below, the radome body assembly 310 may be disposed within or coupled to the lower enclosure 204 (see, e.g., FIG. 3B). The lower enclosure may include protrusions 390 (which may have any shape such as triangular prism, pyramid, tube, or the like) which may be located in the volume 258 and may extend upward (e.g., towards the radome body assembly 310). The protrusions 390 may be sufficiently long so as to contact (and potentially apply pressure to) the PCB assembly 380 in response to coupling between the radome body assembly 310 and the lower enclosure 204. In that regard, the contact between the protrusions 390 and the PCB assembly 380 (when the lower enclosure 204 is coupled to the radome body assembly 310), and/or the pressure applied through the stack to the radome body assembly 310, may be sufficient to retain the layers of the antenna stack assembly together without use of adhesives, fasteners, or other coupling means. This contact (and potential pressure) between the protrusions 390 and the PCB assembly 380 may provide support to one or more layer of the antenna stack assembly 250.

In some embodiments, multiple coupling mechanisms may be used in some or all locations to provide redundant couplings. For example, the elongated member 400 may be used as shown in FIG. 10, and adhesive may be applied between two or more additional layers (e.g., the upper patch antenna layer 330, the antenna spacer 335, and the lower patch antenna layer 370) to provide redundant coupling. As another example, the outer layer 315, radome body assembly, upper patch antenna layer 330, and antenna spacer 335 may be coupled together using a first fastener; the antenna spacer 335, the lower patch antenna layer 370, the dielectric layer 375, and the PCB assembly 380 may be coupled together using a second fastener; and adhesive may be used to couple the lower patch antenna layer 370 to the dielectric layer 375. In this way, additional fasteners may be used to resist relative expansion of two or more layers that may be found to have a relatively different CTE.

In some embodiments, the elongated member 400 may be formed from a same material as the remainder of the radome body assembly 310 (e.g., using a polymer with fibers dispersed therein). In some embodiments, the elongated member 400 may be strengthened, for example by using a coating, to increase its strength. In some embodiments, the elongated member 400 may be formed separate from the radome body assembly 310 and coupled to the radome body assembly 310 using any means (e.g., fasteners, adhesives, chemical bonding, or the like). In these embodiments, the elongated member 400 may be formed from the same or different material as the remainder of the radome body assembly 310. For example, the elongated member 400 may be formed from a different polymer, from a same or different polymer and different fibers (e.g., carbon fiber instead of fiberglass), from a metal, or the like. Similarly, any additional fasteners, connectors, or the like discussed herein may be formed from any material such as a polymer, a polymer and fiber combination, a metal, or the like.

Coupling of Antenna Assembly

Turning to FIGS. 2A, 3B, and 11, the antenna stack assembly