17. Similarly, a digital to analog converter, which may be part of or separate from the transmit circuit 15, converts a digital signal into an analog signal for transmission by the transmit antenna 11.

The controller 19 controls operation of the sensor system 5, including controlling the transmit circuit 15 and the receive circuit 17. The controller 19 may include a processor, also known as a central processing unit (CPU), which may facilitate the operation of the sensor system 5 according to instructions stored in memory 12. The processor may include suitable logic, circuitry, interfaces, and/or code that may be configured to execute a set of instructions stored in the memory 12. The processor may be a hardware component that performs arithmetic, logic, and control operations on data. The processor may be comprised of the arithmetic logic unit, control unit, memory subsystems, and other subsystems. The processor may be responsible for performing signal procession and/or comparison, as well as arithmetic and logical operations on data. The processor may include components for addition, subtraction, multiplication, and division and logical operations such as AND, OR, and NOT. The processor may be responsible for fetching instructions from the memory 12, decoding them, and executing them. The processor may manage the flow of data between different components of the solid constituent sensor as a whole, ensuring that operations are performed in the correct order, and that data is transferred efficiently. The processor may provide fast access to frequently used data and instructions. The processor may include components such as caches, registers, and pipelines, which are designed to minimize the time required to access and manipulate data. The processor may include various other components and subsystems, such as instruction set architecture (ISA), which may define the set of instructions that the processor can execute. The processor may specify the format of instructions and data, the addressing modes used to access memory 12 and I/O devices, and the interrupt and exception handling mechanisms used to manage errors and other events. The processor may include advanced instruction execution capabilities, support for virtualization and parallel processing, and power management mechanisms that reduce energy consumption and heat dissipation. In some embodiments, the controller 19 may be a microcontroller, programmable logic controller (PLCs), or digital signal processors (DSPs) and may be implemented as software components running on general-purpose computers or embedded systems.

A signal storage 14 stores one or more reference signals. The signal storage 14 may be any form of storage that is suitable for storing signals of reference solid samples for use in analyzing (e.g., comparing) the signal detected by the receive antenna 13 to detect and characterize the solid sample. For example, the signal storage 14 may store a database containing signal data related to the reference signals obtained from reference solid samples. The signals may present in any suitable forms, such as, for example, waveforms, spectroscopy diagrams (e.g., spectroscopy lines), frequency spectrum, time-domain signals, amplitude and/or phase signals, imaging signals, modulated signals, etc. The signal storage 14 may be part of the memory 12 or may be at a location separate from the memory 12.

The reference signals stored in the signal storage 14 can be retrieved by, e.g., the processor of the controller 19, and used to analyze the response signal detected by the receive circuit 17. In an embodiment, one or both of the response signal from the receive circuit 17 and the reference signal retrieved from the signal storage 14 can be processed by the controller 19 and transformed to any suitable format that can be compared to each other.

For example, the controller 19 can perform a signal waveform comparison between the signal from the receive circuit 17 and the reference signal to detect or characterize the solid sample 7. The techniques for comparison of signal waveforms are well-known in the art. The signal waveform comparison may be to match the detected signal waveform with the stored reference signal(s) 36 (see FIG. 4). This may assist in detecting a particular constituent in the solid sample; detecting a lack of a particular constituent in the solid sample; determining the molecular makeup of homogenous or heterogeneous solid constituents; determining the total makeup of a solid sample with or without suspended solids; determining the total amount of a combination of multiple constituents in a solid sample; determining whether the solid sample has an expected makeup; identifying the solid sample; etc. The signal comparison may be to determine when the detected signal waveform deviates from the stored reference signal 36 by a predetermined amount. For example, for a detected iron compound sample, when the detected signal waveform deviates by 10% or more (or 3% or more; or 5% or more; etc.) from the stored reference signal 36, that may indicate the iron compound sample has a carbon content deviating from a predetermined content range. Such a deviation of carbon content from the predetermined content range may indicate that the iron compound sample has a problem such as, for example, metal fatigue in terms of its brittleness, hardness, corrosion resistance, etc.

In one embodiment, the controller 19 may optionally be in communication with at least one external device 25 such as a user device and/or a remote server 27, for example through one or more wireless connections such as Bluetooth, wireless data connections such a 4G, 5G, LTE or the like, or Wi-Fi. If provided, the external device 25 and/or remote server 27 may process (or further process) the signals that the controller 19 receives from the receive circuit 17, for example to characterize the solid sample 7. If provided, the external device 25 may be used to provide communication between the sensor system 5 and the remote server 27, for example using a wired data connection or via a wireless data connection or Wi-Fi of the external device 25 to provide the connection to the remote server 27.

With continued reference to FIG. 1, the sensor system 5 may include a sensor housing 29 (shown in dashed lines) that defines an interior space 31. Components of the sensor system 5 may be attached to and/or disposed within the housing 29. For example, the transmit antenna 11 and the receive antenna 13 are attached to the housing 29. In some embodiments, the antennas 11, 13 may be entirely or partially within the interior space 31 of the housing 29. In some embodiments, the antennas 11, 13 may be attached to the housing 29 but at least partially or fully located outside the interior space 31. In some embodiments, the transmit circuit 15, the receive circuit 17 and the controller 19 are attached to the housing 29 and disposed entirely within the sensor housing 29.

FIG. 2 illustrates an example of an antenna array 20 that can be used in the sensor system 5 in place of the antennas 11, 13. The antenna array 20 is depicted as having a first antenna set 32a and a second antenna set 32b. The first antenna set 32a includes a first antenna 34a and a second antenna 34b, and the second antenna set 32b includes a third antenna 36a and a fourth antenna 36b. The first antenna 34a, the second antenna 34b, the third antenna 36a, and the fourth antenna 36b may each include an elongated strip of conductive material with a longitudinal axis (e.g., toward or out of the plane of the paper). The longitudinal axes of the antennas 34a, 34b, 36a, 36b may be parallel to one another, substantially parallel to one another, or generally parallel to one another with a slight angle between one or more of the longitudinal axes of one or more of the antennas 34a, 34b, 36a, 36b. In the embodiment depicted in FIG. 2, the antennas 34a, 34b, 36a, 36b are disposed on a common substrate 38 which is substantially planar as shown in FIG. 2. It is to be understood that the antennas 34a, 34b, 36a, 36b may be disposed on separate planar substrates, angled substrate(s), curved substrate(s), or other substrates. The antennas 34a, 34b, 36a, 36b are depicted in FIG. 2 as disposed on and projecting above the surface of the substrate 38. It is to be understood that the antennas 34a, 34b, 36a, 36b can have other arrangements relative to the substrate such as being flush with the surface of the substrate 38. The substrate 38 may be formed in a manner so it does not interfere with operation of the antenna array 20 as transmit/receive antenna, for example being formed of a non-conductive material such as plastic.

In an embodiment, any one or more of the antennas 34a, 34b, 36a, 36b can be connected to the transmit circuit 15 whereby any one or more of the antennas 34a, 34b, 36a, 36b can function as a transmit antenna. In addition, any one or more of the antennas 34a, 34b, 36a, 36b can be connected to the receive circuit 17 whereby any one or more of the antennas 34a, 34b, 36a, 36b can function as a receive antenna to detect a response that results from transmitting the transmit signal to and/or into the solid sample. Controlling any of a number of antennas to transmit an RF signal and any of a number of antennas to receive an RF signal is disclosed in U.S. Pat. Nos. 11,058,331, 11,193,923, and 11,330,997 each one of which is incorporated herein by reference in its entirety.

The embodiment depicted in FIG. 2 is illustrated as including four antennas, with each antenna set 32a, 32b of the antenna array 20 including two antennas. It is to be understood that a larger or smaller number of antennas can be used.

FIG. 3 illustrates an example of an antenna array 30 that can be used in the sensor system 5 in place of the antennas 11, 13. In FIG. 3, elements that are the same as or similar to elements in FIG. 2 are referenced using the same reference numerals. In this embodiment, the antennas 34a, 34b, 36a, 36b are disposed on a curved or arcuate common substrate 72. The antennas 34a, 34b, 36a, 36b can have the same configuration as the antennas described above for FIG. 2. Although the array 30 is depicted as having four antennas, the array 30 can have a different number of antennas. Due to the curvature of the substrate 72, the upper surface 54a of the antenna 34a faces in the first direction along the axis A, and the upper surface 54b of the antenna 34b faces in a direction A′ that is slightly different than the direction of the axis A, but can be characterized as generally similar to the direction of the axis A. Similarly, the upper surface 56a of the antenna 36a faces in a direction along an axis B′ that is slightly different than the direction of the axis B of the upper surface 56b of the antenna 36b, but can be characterized as generally similar to the direction of the axis B. The axes A, A′ both diverge away from the axes B, B′ and vice versa. The substrate 72 may be formed in a manner so it does not interfere with operation of the antenna array 30 as transmit/receive antenna, for example being formed of a non-conductive material such as plastic.

Referring again to FIG. 1, the transmit antenna 11 can have any form suitable for transmitting the RF/microwave transmit signal 21. For example, the transmit antenna 11 can include a strip or patch of conductive material such as metal or other material that can transmit signals in the radio or microwave frequency range of the electromagnetic spectrum. The transmit antenna 11 may reside on the surface of a substrate or plate, the transmit antenna 11 may partially protrude from (i.e., be partially embedded within) the substrate or plate as depicted in FIGS. 2 and 3, or the transmit antenna 11 may be completely embedded within the substrate or plate. The substrate or plate may be formed in a manner so it does not interfere with operation of the transmit antenna 11, for example being formed of a non-conductive material such as plastic.

The receive antenna 13 can have any form suitable for receiving RF/microwave signals from the solid sample as a result of transmitting the transmit signal by the at least one transmit antenna to and/or into the solid sample. For example, the receive antenna 13 can include a strip or patch of conductive material such as metal or other material that can receive signals in the radio or microwave frequency range of the electromagnetic spectrum. The receive antenna 13 may reside on the surface of a substrate or plate, the receive antenna 13 may partially protrude from (i.e. be partially embedded within) the substrate or plate, or the receive antenna 13 may be completely embedded within the substrate or plate as depicted in FIGS. 2 and 3. The substrate or plate may be formed in a manner so it does not interfere with operation of the receive antenna 13, for example being formed of a non-conductive material such as plastic.

One or both of the antennas 11, 13 may be position adjustable in order to alter the relative position/orientation between the antennas 11, 13, between the transmit antenna 11 and the object surface 71, and between the receive antenna 13 and the object surface 71. For example, the substrate(s) for one or both of the antennas 11, 13 can be mounted to a movable/rotatable mechanism to adjust the relative position/orientation of the antennas 11, 13. Alternatively, the antennas 12, 14 may be position adjustable while keeping the plates 16, 18 stationary. Changing the relative position/orientation between the antennas 11, 13 may change the sensing performance of the solid constituent sensor system 5. In an embodiment, the angles and/or shapes of the antennas 11, 13 may be changed in order to alter the performance of the sensor system 5. An example of an RF constituent sensor with adjustable transmit and/or receive components is disclosed in U.S. Pat. No. 11,696,698, the entire contents of which are incorporated by reference.

FIG. 4 depicts an example of the signal storage 14 of FIG. 1 for storing multiple sample solid constituent reference signals 36. The signal storage 14 may store a single one of the reference signals 36. The reference signals 36 that are stored can be based on the purpose of detecting and characterizing the solid sample 7 of FIG. 1. Many signals 36 are possible. In an embodiment, each signal 36 can represent a different level of a particular constituent, such as carbon content, in the solid sample (e.g., an iron compound or alloy). In an embodiment, each signal 36 may represent a different total amount of a combination of multiple constituents in the solid samples. In an embodiment, each signal 36 can represent a different molecular makeup of homogenous or heterogeneous solid samples. In an embodiment, each signal 36 can represent a different type of metal (e.g. gold, silver, platinum, etc.) for use in identifying the solid sample 7. Different signal sets may be stored. For example, one set of stored reference signals 36 can be provided for one type of constituent in the solid sample, and a second set of stored reference signals 36 can be provided for a second type of constituent in the solid sample.

The reference signals 36 may be stored in a database in the signal storage 14. The database may include one or more database tables, of which every column of a database table represents a particular variable or field, and each row/column of the database table may correspond to a given record of the database. The database tables may list values for each of the variables, and/or for each record of the dataset. Various signal forms of various solid samples can be stored and organized in the database tables.

Referring again to FIG. 1, the controller 19 may be part of the transmit circuit 15, part of the receive circuit 17, or the transmit circuit 15 may include a controller that is separate from a controller included in the receive circuit 17. The solid constituent sensor system 5 can also include a power supply, such as a battery (not shown) which may or may not be rechargeable. In some embodiments, power can be provided from mains power, for example by plugging the solid constituent sensor system 5 into a wall socket via a cord connected to the solid constituent sensor 10, or by another external power source.

Referring to FIG. 5, a flow chart 50 illustrating an example of a solid constituent detection and characterization method, for example using the sensor system 5 described herein, is illustrated, in accordance with at least some embodiments described herein. The processing flow 50 can include one or more operations, actions, or functions as illustrated by one or more of blocks 52, 54 and 56. These various operations, functions, or actions may, for example, correspond to software, program code, or program instructions executable by a processor that causes the functions to be performed. Although illustrated as discrete blocks, obvious modifications may be made, e.g., two or more of the steps or blocks may be re-ordered; further steps or blocks may be added; and various steps or blocks may be divided into additional steps or blocks, combined into fewer steps or blocks, or eliminated, depending on the desired implementation. Further steps or blocks not illustrated in FIG. 5 may be included. Processing flow 50 may begin at block 52.

At block 52 (Transmit RF/microwave signal into solid sample), a transmit signal that is in a radio or microwave frequency range of the electromagnetic spectrum is transmitted from the transmit antenna to and/or into the solid sample. The transmit signal may be a single discrete signal or the signal may be part of a frequency sweep in which multiple signals are transmitted. The frequency sweep may start at an initial frequency and end at a final frequency, with the signals separated by equal or unequal frequency steps. An example of performing frequency sweeps in a radio/microwave frequency sensor is disclosed in U.S. Pat. No. 11,033,208, the entire contents of which are incorporated herein by reference. Processing may proceed from block 52 to block 54.

At block 54 (Detect response from the solid sample), a response is detected at the receive antenna. The response results from transmission of the transmit signal to and/or into the solid sample. The transmitted signal may interact with the solid sample and constituents thereof as it transmits to and/or into the solid sample. The interaction may alter the transmit signal and generate one or more electromagnetic response signals which can be detected by the receive antenna 13 and used to characterize the solid sample. Processing may proceed from block 54 to block 56.

At block 56 (Characterize the solid sample based on the response), the detected response is then used to characterize the solid sample. For example, the detected signal waveform may, in its original form or after being converted to other suitable forms by a processor of the sensor system 5, be compared to one or more stored reference signals as described above for FIG. 4.

In an embodiment, the detected signal may be compared to a single reference signal. When the detected signal deviates from the reference signal, the sensor system 5 can determine that the detected solid sample deviates from an expected chemical composition, and a notification/alarm signal can be sent, for example to an alarm, to notify a user of a related problem of the detected solid sample. The detected signal may need to deviate from the stored signal by a predetermined amount, such as 10% or more, 5% or more, 3% or more, or other quantifiable amount in order to generate a notification signal. The deviation of the detected signal from the stored reference signal can indicate a number of problems such as metal fatigue. The detected signal may also match the reference signal which can indicate that the solid sample has an expected chemical composition and can be used for material identification.

In another embodiment, the detected signal may be compared to multiple reference signals in an effort to look for a match between the detected signal and one of the reference signals. A match can indicate that the solid sample is acceptable or has an expected chemical composition, structure, or property, or a match can indicate that the solid sample is not acceptable or may not have an expected chemical composition, structure, or property.

The solid constituent sensors 5 described herein may form or be incorporated into residential, industrial and/or commercial sensors/detectors. Examples of sensors that the solid constituent sensor 10 can be incorporated into include, but are not limited to, a metal detector, an infrastructure detector, an aircraft parts detector, a soil detector, a plant detector, and many others.