and input signal T4 are provided to four subarrays (C1+45; C1−45; C2+45; C2−45) of the dual-polarization array through the RF matrix 340, respectively.

The input signal T1 is branched by the RF matrix 340 into two branch signals, so that one branch signal reaches the subarray C1+45 with +45° polarization of the first column without phase shift and the other branch signal reaches the subarray C2+45 with +45° polarization of the second column after undergoing the phase shift of −90°. Since the target polarization of the input signal T1 is +45° polarization, the phase shift of −90° is only for beamforming. The two branch signals corresponding to the input signal T1 are radiated by the subarrays C1+45 and C2+45 with a phase difference of −90°, and thus, the beam with the +45° polarization is formed in the spatial direction tilted approximately 30° to the left based on the normal line of the antenna array.

The input signal T2 is branched by the RF matrix 340 into two branch signals, so that one branch signal reaches the subarray C1−45 with the −45° polarization of the first column without phase shift and the other branch signal reaches the subarray C2−45 with the −45° polarization of the second column after undergoing a phase shift of −90°. Since the target polarization of the input signal T2 is −45° polarization, the phase shift of −90° is only for beamforming.

The two branch signals corresponding to the input signal T2 are radiated by the subarrays C1−45 and C2−45 with a phase difference of −90°, and thus, the beam with the −45° polarization is formed in the spatial direction tilted approximately 30° to the left based on the normal line of the antenna array.

The input signal T3 is branched into four branch signals by the RF matrix 340. A first branch signal reaches the subarray C1+45 of the first column without phase shift, and the second branch signal, the third branch signal, and the fourth branch signal reach the subarray C1−45 of the first column, the subarray C2+45 of the second column, and the subarray C2−45 of the second column after undergoing phase shifts of 180°, 90°, and 270°, respectively. The phase shift (180°) of the second branch signal is only for polarization synthesis, the phase shift (90°) of the third branch signal is only for beamforming, and the phase shift (270°) of the fourth branch signal is the sum of the phase shift (90°) for beamforming and the phase shift (180°) for polarization synthesis.

The first branch signal and the second branch signal corresponding to the input signal T3 are radiated by the subarrays C1+45 and C1−45 of the first column C1 with a phase difference of 180°, and thus, a beam with 0° (H) polarization is formed (that is, polarization synthesis occurs). The third branch signal and the fourth branch signal are radiated by the subarrays C1+45 and C1−45 of the first column C1 with the phase difference of 180°, and thus, the beam with 0° (H) polarization is formed (that is, polarization synthesis occurs). In addition, the first branch signal radiated by the subarray C1+45 of the first column and the third branch signal radiated by the subarray C2+45 of the second column have a phase difference of +90° and the second branch signal radiated by the subarray C1−45 of the first column and the fourth branch signal radiated by the subarray C2−45 of the second column have a phase difference of +90°. Therefore, a beam with 0° (H) polarization is formed in a spatial direction tilted approximately 30° to the right based on the normal line of the antenna array.

The input signal T4 is branched into four branch signals by the RF matrix 340, and thus, the first branch signal reaches the subarray C1+45 of the first column without phase shift, and the second branch signal, the third branch signal, and the fourth branch signal reach the subarray C1−45 of the first column, the subarray C2+45 of the second column, and the subarray C2−45 of the second column after undergoing the phase shifts of 180°, 90°, and 270°, respectively.

Since the first branch signal and the second branch signal corresponding to the input signal T4 are radiated by the subarrays C1+45 and C1−45 of the first column C1 with the phase difference of 0°, the beam with 90° (V) polarization is formed (that is, polarization synthesis occurs). Since the third branch signal and the fourth branch signal are radiated by the subarrays C1+45 and C1−45 of the first column C1 with the phase difference of 0°, the beam with 90° (V) polarization is formed (that is, polarization synthesis occurs). In addition, the first branch signal radiated by the subarray C1+45 of the first column and the third branch signal radiated by the subarray C2+45 of the second column have a phase difference of +90°, and the second branch signal radiated by the subarray C1−45 of the first column and the fourth branch signal radiated by the subarray C2−45 of the second column have a phase difference of +90°. Therefore, the beam with 90° polarization is formed in the spatial direction tilted approximately 30° to the right based on the normal line of the antenna array.

FIG. 5a is an example of an RF matrix 500 implemented using a quadrature hybrid coupler (QHC) according to an aspect of the present disclosure. QHC is also referred to as a “branch-line coupler” or a “90° Hybrid coupler”. FIG. 5b illustrates the pattern of beams that can be formed using the RF matrix 500 illustrated in FIG. 5a and the dual polarization characteristics of the beams. The polarization characteristics of the beams illustrated in FIG. 5b are opposite to those illustrated in FIG. 4b. That is, in FIG. 4b, the beam in the 10 o'clock direction has +45°/−45° orthogonal polarization, and in FIG. 5b, the beam in the 2 o'clock direction has +45°/−45° orthogonal polarization. As described with reference to FIG. 2, strictly speaking, the “beam of +/−45° orthogonal polarization is formed in the 2 o'clock direction” means that the beam of +45° linear polarization and the beam of −45° linear polarization are formed in the 2 o'clock direction, and the “beam of V/H orthogonal polarization is formed in the 10 o'clock direction means that the beam of 90° (V) linear polarization and the beam of 0° (H) linear polarization are formed in the 10 o'clock direction.

The RF matrix 500 illustrated in FIG. 5a has four input ports (indicated by white circles), three QHCs 510a, 510b, and 510c formed by conductive strips, and four output ports (indicated by black circles) on a PCB.

As illustrated in the enlarged view of FIG. 5a, QHCs 510a, 510b, and 510c each have four arms (that is, first to fourth arms), and when a signal is input to the first arm, the output appears in the second arm and the third arm and the output does not appear in the fourth arm. Additionally, there is a phase difference of 90° (that is, λ/4) between the output signals of the second arm and the third arm. The QHCs 510a, 510b, and 510c have a top-bottom/left-right symmetrical shape, and when a signal is input to the second arm, the output appears in the first and fourth arms, but the output does not appear in the third arm. In other words, it operates in a completely symmetrical structure.

The input signal T1 reaches the subarray C1+45 of the first column through “the first input port-the first arm of the first QHC 510a-the second arm of the first QHC 510a-the first output port”. In addition, the input signal T1 reaches the subarray C2+45 of the second column through “the first input port-the first arm of the first QHC 510a-(phase delay of 90°)-the third arm of the first QHC 510a-the third output port”. Therefore, from the perspective of the input signal T1, the wireless signal radiated from the subarray C2+45 of the second column has the phase delay of 90° compared to the wireless signal radiated from the subarray C1+45 of the first column, and as illustrated in FIG. 5b, the beam with +45° polarization is formed in the spatial direction tilted approximately 30° to the right based on the normal line of the antenna array.

The input signal T2 reaches the subarray C1−45 of the first column through “the second input port-the first arm of the second QHC 510b-the second arm of the second QHC 510b-the second output port”. In addition, the input signal T2 reaches the subarray (C1−45) of the second column through “the second input port-the first arm of the second QHC 510b-(phase delay of 90°)-the third arm of the second QHC 510b-the fourth output port”. Therefore, from the perspective of the input signal T2, the wireless signal radiated from the subarray C2−45 of the second column has a phase delay of 90° compared to the wireless signal radiated from the subarray C1−45 of the first column, and as illustrated in FIG. 5b, the beam with −45° polarization is formed in the spatial direction tilted approximately 30° to the right based on the normal line of the antenna array.

The input signal T3 reaches the subarray C1+45 of the first column through “the third input port-the fourth arm of the third QHC 510c-(the phase delay of 90°)-the second arm of the third QHC 510c-the fourth arm of the first QHC 510a-(the phase delay of 90°)-the second arm of first QHC 510a-the first output port”. In addition, the input signal T3 reaches the subarray C2+45 through “the third input port-the fourth arm of the third QHC 510c-(the phase delay of 90°)-the second arm of the third QHC 510c-the fourth arm of the first QHC 510a-the third arm of the first QHC 510a-the third output port”. In addition, the input signal T3 reaches the subarray C−45 of the first column through “the third input port-the fourth arm of the third QHC 510c-(the phase delay of 90°)-the third arm of the third QHC 510c-the fourth arm of the second QHC 510b-(the phase delay of 90°)-the second arm of the second QHC 510b-the second output port”. In addition, the input signal T3 reaches the subarray C2−45 of the second column through “the third input port-the fourth arm of the third QHC 510c-(the phase delay of 90°)-the third arm of the third QHC 510c-the fourth arm of the second QHC 510b-the third arm of the second QHC 510b-the fourth output port”.

Therefore, from the perspective of the input signal T3, the wireless signal radiated from the subarray C1−45 of the first column has a phase delay of 0° compared to the wireless signal radiated from the subarray C1+45 of the first column, and the wireless signal radiated from the subarray C2−45 of the second column has a phase delay of 0° compared to the wireless signal radiated from the subarray C2+45 of the second column. As a result, the beam with 90° (V) polarization is formed (that is, polarization synthesis occurs). In addition, the wireless signal radiated from the subarray C1+45 of the first column has a phase delay of 90° compared to the wireless signal radiated from the subarray C2+45 of the second column, and the wireless signal radiated from the subarray C1−45 of the first column has a phase delay of 90° compared to the wireless signal radiated from the subarray C2−45 of the second column. Accordingly, as illustrated in FIG. 5b, the beam with 90° (V) polarization is formed in the spatial direction tilted approximately 30° to the left based on the normal line of the antenna array.

The input signal T4 reaches the subarray C1+45 of the first column through “the fourth input port-the first arm of the third QHC 510c-the second arm of the third QHC 510c-the fourth arm of the first QHC 510a-(phase delay of 90°)-the second arm of the first QHC 510a-the first output port”. In addition, the input signal T4 reaches the subarray (C2+45) in the second column “the fourth input port-the first arm of the third QHC 510c-the second arm of the third QHC 510c-the fourth arm of the first QHC 510a-the third arm of the first QHC 510a-the third output port”. In addition, the input signal T4 reaches the subarray C1−45 of the first column through “the fourth input port-the first arm of the third QHC 510c-(phase delay of 90°)-the third arm of the third QHC 510c-(phase delay of 90°)-the fourth arm of the second QHC 510b-(phase delay of 90°)-the second arm of the second QHC 510b-the second output port”. In addition, the input signal T4 is supplied to the subarray C2−45 of the second column through “the fourth input port-the first arm of the third QHC 510c-(phase delay of 90°)-the third arm of the third QHC 510c-(phase delay of 90°)-the fourth arm of the second QHC 510b-the third arm of the second QHC 510b-the fourth output port”.

Therefore, from the perspective of the input signal T4, the wireless signal radiated from the subarray C1−45 of the first column has a phase delay of 180° compared to the wireless signal radiated from the subarray C1+45 of the first column, and the wireless signal radiated from the subarray C2−45 of the second column has a phase delay of 180° compared to the wireless signal radiated from the subarray C2+45 of the second column. As a result, the beam with 0° (H) polarization is formed (that is, polarization synthesis occurs). In addition, the wireless signal radiated from the subarray C1+45 of the first column has a phase delay of 90° compared to the wireless signal radiated from the subarray C2+45 of the second column, and the wireless signal radiated from the subarray C1−45 of the first column has a phase delay of 90° compared to the wireless signal radiated from the subarray C2−45 of the second column. Therefore, as illustrated in FIG. 5b, a beam with 0° (H) polarization is formed in the spatial direction tilted approximately 30° to the left based on the normal line of the antenna array.