Receiving device

Abstract

A receiving device (1) comprises: a plurality of antenna elements (11) that each generate a first received signal and a second received signal; a plurality of second phase shifters (13b) that adjust the phase of each second received signal on the basis of a predetermined phase adjustment amount; a plurality of second gain adjusters (14b) that adjust the amplitude of each second received signal on the basis of a predetermined gain suppression amount; a first combining circuit (15) that combines the plurality of first received signals to generate a first combined signal; a second combining circuit (16) that combines the second received signals of which the phase and amplitude have been adjusted, to generate a second combined signal; and a third combining circuit (17) that combines the first combined signal and the second combined signal. The predetermined gain suppression amount is a gain suppression amount that brings the amplitude of the second combined signal closer to the amplitude of a cross polarization component included in the first combined signal. The predetermined phase adjustment amount is a phase adjustment amount that causes the phase of the second combined signal to be opposite to the phase of the cross polarization component included in the first combined signal.

Description

Receiving device

[0001] The present disclosure relates to a receiving device.

[0002] Radio waves received by a phased array receiving device include a primary polarization component and a cross-polarization component that intersects with the primary polarization component. As the scanning range of the receiving device becomes wider, the cross-polarization component increases. If the amplitude of the cross-polarization component increases relative to the amplitude of the primary polarization component, the communication quality of the receiving device deteriorates. Some receiving devices have a function to reduce the cross-polarization component to prevent deterioration of communication quality. An example of this type of receiving device is disclosed in Patent Document 1.

[0003] The antenna device disclosed in Patent Document 1 has a circularly polarized element antenna and a cross-polarized element antenna, and generates a signal with the same amplitude and opposite phase as the cross-polarized component contained in the output of the circularly polarized element antenna in the cross-polarized element antenna, and suppresses the cross-polarized component by combining the generated signal with the output of the circularly polarized element antenna.

[0004] JP 2011-91625 A

[0005] In the antenna device disclosed in Patent Document 1, in order to suppress the cross-polarized component contained in the output of the circularly polarized element antenna, some of the antenna elements must be cross-polarized element antennas. Therefore, the antenna gain of the antenna device disclosed in Patent Document 1 is lower than that of an antenna device in which each antenna element is a circularly polarized element antenna.

[0006] The present disclosure has been made in consideration of the above circumstances, and aims to provide a receiving device with high antenna gain and high communication quality.

[0007] To achieve the above object, a receiving device according to the present disclosure includes a plurality of antenna elements, a plurality of second phase shifters, a plurality of second gain adjusters, a first combining circuit, a second combining circuit, and a third combining circuit. The antenna elements receive radio waves including a primary polarization component and a cross-polarization component that crosses the primary polarization component, and generate a first received signal based on the primary polarization component and a second received signal based on the cross-polarization component. The second phase shifters are associated with the antenna elements and adjust the phase of the second received signal generated by the corresponding antenna element based on a predetermined phase adjustment amount. The second gain adjusters are associated with the antenna elements and adjust the amplitude of the second received signal generated by the corresponding antenna element based on a predetermined gain suppression amount. The first combining circuit combines the plurality of first received signals to generate a first combined signal. The second combining circuit combines the plurality of second received signals whose phases have been adjusted by the second phase shifters and whose amplitudes have been adjusted by the second gain adjusters to generate a second combined signal. The third combining circuit combines the first combined signal and the second combined signal. The predetermined gain suppression amount is a gain suppression amount that brings the amplitude of the second combined signal closer to the amplitude of the cross polarization component included in the first combined signal, and the predetermined phase adjustment amount is a phase adjustment amount that makes the phase of the second combined signal opposite to the phase of the cross polarization component included in the first combined signal.

[0008] A receiving device according to the present disclosure adjusts the amplitude of a second received signal based on a gain suppression amount that brings the amplitude of a second combined signal obtained by combining second received signals closer to the amplitude of a cross-polarized component included in a first combined signal obtained by combining first received signals. The receiving device adjusts the phase of the second received signal based on a phase adjustment amount that makes the phase of the second combined signal opposite the phase of the cross-polarized component included in the first combined signal. By combining the first and second combined signals, the cross-polarized component included in the first combined signal is canceled by the second combined signal, resulting in a receiving device with high antenna gain and communication quality.

[0009] 1 is a block diagram showing a configuration of a receiving device according to an embodiment; 2 is a diagram showing a hardware configuration of a control unit of a receiving device according to an embodiment; 3 is a diagram showing an example of a relationship between a main polarization component and a cross polarization component contained in a first combined signal in an embodiment; 4 is a diagram showing an example of a relationship between a cross polarization component contained in a first combined signal, a second combined signal, and a cross polarization component contained in a combined result of the first combined signal and the second combined signal in an embodiment; 5 is a block diagram showing a configuration of a first modified example of a receiving device according to an embodiment; 6 is a block diagram showing a configuration of a second modified example of a receiving device according to an embodiment;

[0010] Hereinafter, a receiving device according to an embodiment of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or equivalent parts are designated by the same reference numerals, and their description will not be repeated in principle.

[0011] A receiving device according to an embodiment will be described using an active phased array antenna as an example of a receiving device. The receiving device 1 shown in Fig. 1 captures radio waves from a satellite, for example, linearly polarized waves emitted from the satellite. Here, capturing radio waves means receiving the radio waves. The receiving device 1 includes a plurality of antenna elements 11 that receive the radio waves and generate a first received signal and a second received signal, an antenna unit 10 that adjusts the phase and amplitude of the first received signal and the second received signal, respectively, and outputs a combined signal, and a control unit 20 that controls each unit of the receiving device 1 described above.

[0012] The antenna unit 10 includes a low-noise amplifier 12 that amplifies the first received signal or the second received signal, a plurality of first phase shifters 13a that adjust the phase of the first received signal, a plurality of second phase shifters 13b that adjust the phase of the second received signal, a plurality of first gain adjusters 14a that adjust the amplitude of the first received signal, and a plurality of second gain adjusters 14b that adjust the amplitude of the second received signal. The antenna unit 10 further includes a first combining circuit 15 that combines the first received signals to generate a first combined signal, a second combining circuit 16 that combines the second received signals to generate a second combined signal, and a third combining circuit 17 that combines the first and second combined signals. The antenna unit 10 is configured on a single board. The low-noise amplifier 12, the first phase shifter 13a, the second phase shifter 13b, the first gain adjuster 14a, and the second gain adjuster 14b may each be discrete components or may be configured on a single IC (Integrated Circuit) chip.

[0013] The control unit 20 includes an amplitude detection unit 21 that detects the amplitudes of the first and second combined signals, a gain suppression amount determination unit 22 that determines a gain suppression amount indicating the amount of amplitude adjustment in the second gain adjuster 14 b from the amplitudes of the first and second combined signals, a phase detection unit 23 that detects the phases of the first and second combined signals, and a phase adjustment amount determination unit 24 that determines a phase adjustment amount indicating the amount of phase adjustment in the second phase shifter 13 b from the phase of the first combined signal. In Figure 1, to avoid complicating the drawing, the lines connecting the control unit 20 to other components of the receiving device 1 are simplified or omitted.

[0014] The radio waves received by the receiving device 1 include a main polarization component and a cross polarization component that crosses the main polarization component. As an example, in a receiving device 1 that receives vertically polarized waves, the main polarization component is vertically polarized and the cross polarization component is horizontally polarized. As another example, in a receiving device 1 that receives horizontally polarized waves, the main polarization component is horizontally polarized and the cross polarization component is vertically polarized.

[0015] The antenna element 11 receives radio waves including a main polarization component and a cross polarization component, and generates a first reception signal based on the main polarization component and a second reception signal based on the cross polarization component. Specifically, by attaching a port for receiving vertically polarized waves and a port for receiving horizontally polarized waves to the circular patch antenna, the antenna element 11 is able to receive the main polarization component and the cross polarization component. The first reception signal generated by the antenna element 11 is a signal based on the main polarization component, but also includes the cross polarization component in addition to the main polarization component.

[0016] The low-noise amplifier 12 amplifies the first received signal or the second received signal input from the antenna element 11 and outputs the amplified first received signal or the second received signal. The low-noise amplifier 12 that receives the first received signal from the antenna element 11 is referred to as low-noise amplifier 12a, and the low-noise amplifier 12 that receives the second received signal from the antenna element 11 is referred to as low-noise amplifier 12b. As shown in Fig. 1, two low-noise amplifiers 12, specifically low-noise amplifiers 12a and 12b, are provided for one antenna element 11.

[0017] The first phase shifter 13a is provided for each antenna element 11. Based on a predetermined phase shift amount, the first phase shifter 13a adjusts the phase of the first received signal generated by the corresponding antenna element 11. In detail, the first phase shifter 13a adjusts the phase of the first received signal generated by the corresponding antenna element 11 and amplified by the low-noise amplifier 12a.

[0018] A second phase shifter 13b is provided for each antenna element 11. The second phase shifter 13b adjusts a predetermined phase shift amount in accordance with a phase adjustment amount supplied from the control unit 20, and adjusts the phase of the second received signal generated by the corresponding antenna element 11 based on the adjusted phase shift amount. When no phase adjustment amount is supplied from the control unit 20, the second phase shifter 13b adjusts the phase of the second received signal generated by the corresponding antenna element 11 based on the predetermined phase shift amount, and reduces the gain of the low-noise amplifier 12b or the second gain adjuster 14b to sufficiently reduce the amplitude of the second received signal.

[0019] The first phase shifter 13a and the second phase shifter 13b receive and store information about a predetermined phase shift amount for obtaining a desired antenna directivity in the receiving device 1 from the control unit 20 or an external device other than the receiving device 1. In detail, the first phase shifter 13a adjusts the phase by a predetermined phase shift amount to obtain the desired antenna directivity, and the second phase shifter 13b adjusts the phase by a phase shift amount obtained by changing the predetermined phase shift amount to a predetermined phase adjustment amount to obtain the desired antenna directivity. As a result of the first phase shifter 13a and the second phase shifter 13b performing the phase adjustments, the phase of the received signal generated by the antenna element 11, amplified by the low-noise amplifier 12b, and phase-adjusted by the second phase shifter 13b approaches the opposite phase of the cross-polarized component included in the received signal generated by the antenna element 11, amplified by the low-noise amplifier 12a, and phase-adjusted by the first phase shifter 13a.

[0020] A first gain adjuster 14a is provided for each antenna element 11. Based on a predetermined gain, the first gain adjuster 14a adjusts the amplitude of the first reception signal generated by the corresponding antenna element 11. In detail, the first gain adjuster 14a adjusts the amplitude of the first reception signal that is generated by the antenna element 11, amplified by the low-noise amplifier 12a, and whose phase is adjusted by the first phase shifter 13a.

[0021] The second gain adjuster 14b is provided for each antenna element 11. The second gain adjuster 14b adjusts a predetermined gain in accordance with a gain suppression amount supplied from the control unit 20, and adjusts the amplitude of the second reception signal generated by the corresponding antenna element 11 based on the adjusted gain. In detail, the second gain adjuster 14b adjusts the amplitude of the second reception signal, which is generated by the antenna element 11, amplified by the low-noise amplifier 12b, and whose phase is adjusted by the second phase shifter 13b, based on the adjusted gain. When a gain suppression amount is not supplied from the control unit 20, the second gain adjuster 14b reduces the gain of the second gain adjuster 14b to sufficiently reduce the amplitude of the second reception signal generated by the corresponding antenna element 11.

[0022] The first gain adjuster 14a and the second gain adjuster 14b hold information about target gains determined based on the magnitude of the amplitudes of the first and second received signals, the linearity of the amplifiers, etc. The first gain adjuster 14a and the second gain adjuster 14b are, for example, variable amplifiers with adjustable gains. The variable amplifiers adjust the gains in accordance with the gain suppression amount supplied from the control unit 20, and amplify the input received signals.

[0023] The first combining circuit 15 combines the input first received signals. Specifically, the first combining circuit 15 combines the first received signals generated by the antenna elements 11, amplified by the low-noise amplifier 12a, phase-adjusted by the first phase shifter 13a, and amplitude-adjusted by the first gain adjuster 14a to generate a first combined signal. The second combining circuit 16 combines the second received signals generated by the antenna elements 11, amplified by the low-noise amplifier 12b, phase-adjusted by the second phase shifter 13b, and amplitude-adjusted by the second gain adjuster 14b to generate a second combined signal.

[0024] The third combining circuit 17 combines the first combined signal and the second combined signal. The third combining circuit 17 transmits the signal obtained by combining the first combined signal and the second combined signal to a receiving circuit (not shown). The first combined signal is generated by combining the first received signal based on the primary polarization component, but includes a cross-polarization component. The third combining circuit 17 combines the first combined signal with the second combined signal, which is generated to cancel the cross-polarization component included in the first combined signal, so that the cross-polarization component included in the first combined signal is canceled by the second combined signal. As a result, the cross-polarization component included in the output of the third combining circuit 17 is sufficiently reduced.

[0025] In order to sufficiently reduce the cross-polarized component contained in the first combined signal, the control unit 20 adjusts the amount of gain suppression supplied to the second gain adjuster 14b and the amount of phase adjustment supplied to the second phase shifter 13b.

[0026] 2 shows the hardware configuration of the control unit 20 included in the receiving device 1 having the above configuration. The control unit 20 includes a processor 81, a memory 82, and an interface 83. The processor 81, the memory 82, and the interface 83 are connected to one another via a bus 80. The processor 81 includes any electronic circuit including a transistor, and is considered to be a circuit or a processor circuit.

[0027] The functions of the control unit 20 are realized by software, firmware, which is software built into the electronic device, or a combination of software and firmware. The software is written as a program and stored in the memory 82. The processor 81 reads and executes the program stored in the memory 82, thereby realizing the functions of the above-mentioned units. In other words, the memory 82 stores a program for executing the processing of the control unit 20.

[0028] The memory 82 includes, for example, non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read-Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable and Programmable Read-Only Memory), magnetic disk, flexible disk, optical disk, compact disk, mini disk, DVD (Digital Versatile Disc), etc.

[0029] The control unit 20 is connected to the antenna unit 10 via an interface 83. The interface 83 has an interface module that complies with one or more standards depending on the connection destination.

[0030] The control unit 20 included in the receiving device 1 having the above configuration determines the amount of gain suppression. The determined amount of gain suppression is stored in the memory 82 and supplied to the second gain adjuster 14b. Specifically, the amplitude detection unit 21 included in the control unit 20 detects the amplitudes of the main polarization component and the cross polarization component included in the first combined signal output by the first combining circuit 15 and the amplitude of the second combined signal output by the second combining circuit 16. The radiation pattern shown in FIG. 3 is obtained from the amplitudes of the main polarization component and the cross polarization component included in the first combined signal detected by the amplitude detection unit 21. The horizontal axis of FIG. 3 represents the angle (unit: degrees) from the front direction of the receiving device 1, and the vertical axis represents the amplitude (unit: dB). In the example of FIG. 3, at a scanning angle of 45 degrees, the difference between the amplitude of the main polarization component (solid line) and the amplitude of the cross polarization component (dotted line) included in the first combined signal is 10 dB. Alternatively, a separate device may be used to detect the amplitudes of the first and second composite signals and determine the gain suppression amounts before the operation of the receiving device 1 is started. In this case, the amplitude detection unit 21 and the gain suppression amount determination unit 22 are not necessarily required as components of the receiving device 1. The predetermined gain suppression amounts are stored in the memory 82.

[0031] The gain suppression amount determiner 22 determines the gain suppression amount based on the difference between the amplitude of the cross-polarized component included in the first combined signal and the amplitude of the second combined signal. The gain suppression amount is, for example, a numerical value representing the amount of attenuation in the second gain adjuster 14b, and is 1 when no attenuation is performed. For example, when the radiation pattern shown in FIG. 3 is obtained, the gain suppression amount determiner 22 determines the gain suppression amount for reducing the amplitude of the cross-polarized component included in the first combined signal by 8 dB. The gain suppression amount may be any value included in a gain target range including a gain target value determined by the difference between the amplitude of the cross-polarized component included in the first combined signal and the amplitude of the second combined signal. For example, the gain target range is a range of ±1 dB from the gain target value. When the gain target value is 8 dB, the gain target range may be a 2 dB range centered on 8 dB, specifically, a range of 7 dB or more and 9 dB or less.

[0032] The control unit 20 also determines a phase adjustment amount. Specifically, the phase detection unit 23 included in the control unit 20 detects the phase of the cross-polarization component included in the first combined signal output by the first combining circuit 15. The phase adjustment amount determination unit 24 determines a phase adjustment amount for making the phase of the second combined signal the opposite phase of the cross-polarization component included in the first combined signal, based on the phase detected by the phase detection unit 23. The phase adjustment amount may be a value included in a phase target range that includes a phase target value for making the phase of the second combined signal the opposite phase of the cross-polarization component included in the first combined signal. For example, the phase target range is a range of ±15° of the phase target value. The phase adjustment amount determination unit 24 stores the determined phase adjustment amount in the memory 82 and supplies it to the second phase shifter 13b. Note that the phases of the first combined signal and the second combined signal may be detected and the phase adjustment amount determined using a separate device before operation of the receiving device 1 is started. In this case, the phase detector 23 and the phase adjustment amount determiner 24 are not necessarily required as components of the receiver 1. The phase adjustment amount determined in advance is stored in the memory .

[0033] As described above, the second phase shifter 13b adjusts the phase of the second received signal based on the phase adjustment amount. The second gain adjuster 14b adjusts the amplitude of the second received signal based on the gain suppression amount. The first received signal, which is generated by the antenna element 11, amplified by the low-noise amplifier 12a, phase-adjusted by the first phase shifter 13a, and amplitude-adjusted by the first gain adjuster 14a, is combined to obtain a first combined signal. The second received signal, which is generated by the antenna element 11, amplified by the low-noise amplifier 12b, phase-adjusted by the second phase shifter 13b, and amplitude-adjusted by the second gain adjuster 14b, is combined to obtain a second combined signal. By performing amplitude adjustment based on the gain suppression amount and phase adjustment based on the phase adjustment amount as described above, it is possible to cancel out the cross-polarized component included in the first combined signal with the second combined signal.

[0034] An example of canceling the cross-polarization component contained in the first combined signal by the second combined signal is shown in Figure 4. The horizontal axis of Figure 4 represents the angle (unit: degrees) from the front direction of the receiving device 1, and the vertical axis represents the amplitude (unit: dB). In Figure 4, the cross-polarization component contained in the first combined signal is shown by a dotted line, and the second combined signal is shown by a thin solid line. The cross-polarization component contained in the result of combining the first combined signal and the second combined signal is shown by a thick solid line. At a scanning angle of 45 degrees, the cross-polarization component contained in the result of combining the first combined signal and the second combined signal is reduced by 20 dB, and the communication quality of the receiving device 1 is improved compared to the example of Figure 3.

[0035] As described above, the gain suppression amount determiner 22 included in the receiving device 1 according to the embodiment determines a gain suppression amount that brings the amplitude of the second combined signal output by the second combining circuit 16 closer to the amplitude of the cross polarization component included in the first combined signal output by the first combining circuit 15. The second gain adjuster 14b included in the receiving device 1 adjusts the amplitude of the second received signal generated by the corresponding antenna element 11 based on the gain suppression amount determined as described above. As a result, the amplitude of the second combined signal obtained by combining the second received signals generated by the antenna elements 11 approaches the amplitude of the cross polarization component included in the first combined signal obtained by combining the first received signals generated by the antenna elements 11.

[0036] The phase adjustment amount determiner 24 included in the receiving device 1 determines a phase adjustment amount for making the phase of the second combined signal obtained by combining the second received signals generated by the antenna element 11 the opposite phase to the phase of the cross polarization component included in the first combined signal obtained by combining the first received signals generated by the antenna element 11. The second phase shifter 13b adjusts the phase of the second received signal generated by the antenna element 11 based on the phase adjustment amount determined as described above.

[0037] The third combining circuit 17 combines the first combined signal generated by combining the first received signal with the second combined signal generated by combining the second received signal with the first combining circuit 15, thereby canceling out the cross-polarized component contained in the first combined signal and the second combined signal. This results in a receiving device 1 with high communication quality. Furthermore, the receiving device 1 does not need to provide an antenna element that receives only the cross-polarized component in order to reduce the cross-polarized component, and therefore the antenna gain is not reduced. In other words, the antenna gain of the receiving device 1 is higher than that of a receiving device that uses part of its antenna element to receive the cross-polarized component.

[0038] The present disclosure is not limited to the above-described embodiment. The receiving device 1 may receive not only linearly polarized waves but also circularly polarized waves. Fig. 5 shows an example of a receiving device 2 that receives circularly polarized waves. As one example, in a receiving device 2 that is intended to receive right-handed circularly polarized waves, the main polarization component is right-handed circularly polarized waves and the cross polarization component is left-handed circularly polarized waves. As another example, in a receiving device 2 that is intended to receive left-handed circularly polarized waves, the main polarization component is left-handed circularly polarized waves and the cross polarization component is right-handed circularly polarized waves.

[0039] The receiving device 2 comprises a plurality of antenna elements 11 that receive radio waves including a main polarization component and a cross polarization component and generate a first received signal based on the main polarization component and a second received signal based on the cross polarization component, an antenna unit 10 that adjusts the phase and amplitude of the first received signal and the second received signal, respectively, and outputs a composite signal, and a control unit 20 that controls each part of the receiving device 2 described above.

[0040] The antenna unit 10 includes a low-noise amplifier 12 that amplifies the first received signal and the second received signal, a plurality of first phase shifters 13a that adjust the phase of the first received signal, a plurality of second phase shifters 13b that adjust the phase of the second received signal, a plurality of first gain adjusters 14a that adjust the amplitude of the first received signal, a plurality of second gain adjusters 14b that adjust the amplitude of the second received signal, a first combining circuit 15 that combines the first received signals to generate a first combined signal, a second combining circuit 16 that combines the second received signals to generate a second combined signal, and a third combining circuit 17 that combines the first combined signal and the second combined signal.

[0041] A circular patch antenna is equipped with a port for receiving vertically polarized waves and a port for receiving horizontally polarized waves. By providing a 90-degree phase difference between the vertically polarized waves and the horizontally polarized waves, a right-handed circularly polarized wave is obtained, and by providing a -90-degree phase difference between the vertically polarized waves and the horizontally polarized waves, a left-handed circularly polarized wave is obtained. The antenna element 11 receives radio waves and outputs vertically polarized waves and horizontally polarized waves. The vertically polarized waves and horizontally polarized waves each include a main polarization component and a cross-polarized component. In other words, the vertically polarized waves output by the antenna element 11 include a vertical component of a first received signal based on the main polarization component and a vertical component of a second received signal based on the cross-polarized component. The horizontally polarized waves output by the antenna element 11 include a horizontal component of a first received signal based on the main polarization component and a horizontal component of a second received signal based on the cross-polarized component.

[0042] Two low noise amplifiers 12, two first phase shifters 13a, two second phase shifters 13b, two first gain adjusters 14a, and two second gain adjusters 14b are provided corresponding to each of the antenna elements 11.

[0043] Of the two low-noise amplifiers 12 associated with the same antenna element 11, the low-noise amplifier 12 that amplifies the vertically polarized wave output by the antenna element 11 is referred to as low-noise amplifier 121, and the low-noise amplifier 12 that amplifies the horizontally polarized wave output by the antenna element 11 is referred to as low-noise amplifier 122. The operations of the low-noise amplifiers 121 and 122 are similar to those of the low-noise amplifier 12.

[0044] Of the two first phase shifters 13a associated with the same antenna element 11, the first phase shifter 13a that adjusts the phase of the vertically polarized wave will be referred to as the first phase shifter 131a, and the first phase shifter 13a that adjusts the phase of the horizontally polarized wave will be referred to as the first phase shifter 132a. Of the two second phase shifters 13b associated with the same antenna element 11, the second phase shifter 13b that adjusts the phase of the vertically polarized wave will be referred to as the second phase shifter 131b, and the second phase shifter 13b that adjusts the phase of the horizontally polarized wave will be referred to as the second phase shifter 132b. The operation of the first phase shifters 131a and 132a is the same as that of the first phase shifter 13a. The operation of the second phase shifters 131b and 132b is the same as that of the second phase shifter 13b.

[0045] As an example, when right-handed circularly polarized waves are the main polarization component, the phase shift amounts that result in a phase difference of 90 degrees between the outputs of the first phase shifters 131a and 132a are set in advance in the first phase shifters 131a and 132a, and the phase shift amounts that result in a phase difference of −90 degrees between the outputs of the second phase shifters 131b and 132b are set in advance in the second phase shifters 131b and 132b. As a result, by combining the outputs of the first phase shifters 131a and 132a, right-handed circularly polarized waves, which are the main polarization component, are obtained, and by combining the outputs of the second phase shifters 131b and 132b, left-handed circularly polarized waves, which are the cross polarization component, are obtained.

[0046] Of the two first gain adjusters 14a associated with the same antenna element 11, the first gain adjuster 14a that adjusts the amplitude of the vertical component of the first received signal will be referred to as the first gain adjuster 141a, and the first gain adjuster 14a that adjusts the amplitude of the horizontal component of the first received signal will be referred to as the first gain adjuster 142a. Of the two second gain adjusters 14b associated with the same antenna element 11, the second gain adjuster 14b that adjusts the amplitude of the vertical component of the second received signal will be referred to as the second gain adjuster 141b, and the second gain adjuster 14b that adjusts the amplitude of the horizontal component of the second received signal will be referred to as the second gain adjuster 142b. The operation of the first gain adjusters 141a and 142a is similar to that of the first gain adjuster 14a. The operation of the second gain adjusters 141b and 142b is similar to that of the second gain adjuster 14b.

[0047] The vertically polarized wave generated by antenna element 11 is amplified by low-noise amplifier 121 and supplied to first phase shifter 131a and second phase shifter 131b. The vertically polarized wave, whose phase has been adjusted by first phase shifter 131a and whose amplitude has been adjusted by first gain adjuster 141a, is supplied to first combiner circuit 15. The vertically polarized wave, whose phase has been adjusted by second phase shifter 131b and whose amplitude has been adjusted by second gain adjuster 141b, is supplied to second combiner circuit 16.

[0048] The horizontally polarized wave generated by antenna element 11 is amplified by low-noise amplifier 122 and supplied to first phase shifter 132a and second phase shifter 132b. The horizontally polarized wave, whose phase has been adjusted by first phase shifter 132a and whose amplitude has been adjusted by first gain adjuster 142a, is supplied to first combiner circuit 15. The horizontally polarized wave, whose phase has been adjusted by second phase shifter 132b and whose amplitude has been adjusted by second gain adjuster 142b, is supplied to second combiner circuit 16.

[0049] A main polarization component, for example, a right-handed circularly polarized wave, is obtained by combining in the first combining circuit 15 the vertical polarization whose phase has been adjusted by the first phase shifter 131a and the amplitude whose amplitude has been adjusted by the first gain adjuster 141a and the horizontal polarization whose phase has been adjusted by the first phase shifter 132a and the amplitude whose amplitude has been adjusted by the first gain adjuster 142a. A cross polarization component, for example, a left-handed circularly polarized wave, is obtained by combining in the second combining circuit 16 the vertical polarization whose phase has been adjusted by the second phase shifter 131b and the amplitude whose amplitude has been adjusted by the second gain adjuster 141b and the horizontal polarization whose phase has been adjusted by the second phase shifter 132b and the amplitude whose amplitude has been adjusted by the second gain adjuster 142b.

[0050] The operation of the control unit 20 included in the receiving device 2 is similar to the operation performed by the control unit 20 included in the receiving device 1. The amplitude detection unit 21 detects the amplitudes of the main polarization component and the cross polarization component included in the first combined signal and the amplitude of the second combined signal. The gain suppression amount determination unit 22 calculates a gain suppression amount that brings the amplitude of the second combined signal closer to the amplitude of the cross polarization component included in the first combined signal. The gain suppression amount determination unit 22 stores the calculated gain suppression amount in the memory 82 and supplies it to the second gain adjusters 141b and 142b. The phase adjustment amount determination unit 24 calculates a phase adjustment amount that makes the phase of the second combined signal opposite the phase of the cross polarization component included in the first combined signal. The phase adjustment amount determination unit 24 stores the calculated phase adjustment amount in the memory 82 and supplies it to the second phase shifters 131b and 132b. Note that the amplitudes of the first combined signal and the second combined signal may be detected and the gain suppression amount determined using a separate device before operation of the receiving device 2 is started. In this case, the receiving device 2 does not necessarily require the amplitude detection unit 21 and the gain suppression amount determination unit 22. The predetermined gain suppression amount is stored in the memory 82. Another device may be used to detect the phases of the first combined signal and the second combined signal and determine the phase adjustment amount before the receiving device 2 starts operating. In this case, the receiving device 2 does not necessarily require the phase detection unit 23 and the phase adjustment amount determination unit 24. The predetermined phase adjustment amount is stored in the memory 82.

[0051] Based on the phase adjustment amount calculated as described above, second phase shifters 131b and 132b adjust the phases of the vertically polarized waves and the horizontally polarized waves, respectively. Based on the gain suppression amount calculated as described above, second gain adjusters 141b and 142b adjust the amplitudes of the vertically polarized waves and the horizontally polarized waves, respectively. As a result, even in a receiver 2 that receives circularly polarized waves, the cross polarization component included in the first combined signal is canceled out by the second combined signal, resulting in a receiver 2 with high communication quality.

[0052] The receiving device according to the embodiment of the present disclosure is not limited to receiving linearly polarized waves, and may also receive obliquely polarized waves. Furthermore, the receiving device according to the embodiment of the present disclosure may be used, for example, in a satellite communication system including an antenna, a transceiver, a frequency converter, a modem, and a control device. As another example, the receiving device may be used in a radar device including an antenna, a transceiver unit, a control unit, a display unit, and an operation unit.

[0053] The configurations of the receiving devices 1 and 2 are not limited to the above examples. As an example, FIG. 6 shows a receiving device 3 that adjusts the amplitude of the second combined signal based on the gain suppression amount and adjusts the phase of the second combined signal based on the phase adjustment amount. The antenna unit 10 included in the receiving device 3 further includes, in addition to the configuration of the antenna unit 10 included in the receiving device 1, a third gain adjuster 18 that adjusts the amplitude of the second combined signal based on the gain suppression amount supplied from the control unit 20, and a third phase shifter 19 that adjusts the phase of the second combined signal based on the phase adjustment amount supplied from the control unit 20. The configuration of the third gain adjuster 18 is similar to the configuration of the second gain adjuster 14b included in the receiving device 1. The configuration of the third phase shifter 19 is similar to the configuration of the second phase shifter 13b included in the receiving device 1.

[0054] The first phase shifter 13a and the second phase shifter 13b provided in the receiving device 3 have the same configuration and operate in the same way. The first phase shifter 13a and the second phase shifter 13b adjust the phases of the first received signal and the second received signal, respectively, based on a predetermined phase shift amount. The first gain adjuster 14a and the second gain adjuster 14b provided in the receiving device 3 have the same configuration and operate in the same way. The first gain adjuster 14a and the second gain adjuster 14b adjust the amplitudes of the first received signal and the second received signal, respectively, based on a predetermined gain.

[0055] The amplitude detector 21 detects the amplitudes of the co-polarized and cross-polarized components included in the first combined signal and the amplitude of the second combined signal. The gain suppression amount determiner 22 calculates a gain suppression amount that brings the amplitude of the second combined signal closer to the amplitude of the cross-polarized component included in the first combined signal. The gain suppression amount determiner 22 stores the calculated gain suppression amount in the memory 82 and supplies it to the third gain adjuster 18. The third gain adjuster 18 adjusts the amplitude of the second combined signal based on the received gain suppression amount. Note that a separate device may be used to detect the amplitudes of the first combined signal and the second combined signal and determine the gain suppression amount before the receiver 3 begins operation. In this case, the receiver 3 does not necessarily require the amplitude detector 21 and the gain suppression amount determiner 22. The predetermined gain suppression amount is stored in the memory 82.

[0056] The phase detector 23 detects the phase of the first combined signal. The phase adjustment amount determiner 24 determines, from the phase detected by the phase detector 23, a phase adjustment amount for making the phase of the second combined signal the opposite phase of the cross-polarized component contained in the first combined signal. The phase adjustment amount determiner 24 stores the determined phase adjustment amount in the memory 82 and supplies it to the third phase shifter 19. The third phase shifter 19 adjusts the phase of the second combined signal based on the supplied phase adjustment amount. Note that a separate device may be used to detect the phases of the first combined signal and the second combined signal and determine the phase adjustment amount before operation of the receiving device 3 begins. In this case, the phase detector 23 and the phase adjustment amount determiner 24 are not necessarily required as part of the configuration of the receiving device 3. The predetermined phase adjustment amount is stored in the memory 82.

[0057] As described above, the first composite signal and the second composite signal whose amplitude has been adjusted by the third gain adjuster 18 and whose phase has been adjusted by the third phase shifter 19 are combined by the third combining circuit 17, so that the cross-polarization component contained in the first composite signal can be canceled out by the second composite signal.

[0058] As another example, in the receiving device according to the embodiment of the present disclosure, the connection order of the low-noise amplifier 12a, the first phase shifter 13a, and the first gain adjuster 14a may be interchanged. For example, the first reception signal generated by the antenna element 11 may be amplified by the low-noise amplifier 12a, its amplitude may be adjusted by the first gain adjuster 14a, and its phase may be adjusted by the first phase shifter 13a. Similarly, the connection order of the low-noise amplifier 12b, the second phase shifter 13b, and the second gain adjuster 14b may be interchanged. For example, the second reception signal generated by the antenna element 11 may be amplified by the low-noise amplifier 12b, its amplitude may be adjusted by the second gain adjuster 14b, and its phase may be adjusted by the second phase shifter 13b.

[0059] As another example, the receiving device according to the embodiment of the present disclosure may not include the low-noise amplifier 12. Similarly, the receiving device according to the embodiment of the present disclosure may not include the first phase shifter 13a and the first gain adjuster 14a. When the first phase shifter 13a is not included, the phase shift amount of the second phase shifter 13b is set to a value obtained by subtracting the phase shift amount of the first phase shifter 13a from the phase shift amount of the second phase shifter 13b when the first phase shifter 13a is included. When the first gain adjuster 14a is not included, the gain of the second gain adjuster 14b is set to a value obtained by dividing the gain of the second gain adjuster 14b when the first gain adjuster 14a is included by the gain of the first gain adjuster 14a.

[0060] As another example, the first gain adjuster 14 a, the second gain adjuster 14 b, and the third gain adjuster 18 may each include an amplifier with a fixed gain and a variable attenuator with an adjustable attenuation amount. The amplifier amplifies the input received signal and supplies the amplified signal to the variable attenuator. The variable attenuator attenuates the received signal amplified by the amplifier in accordance with the gain suppression amount supplied from the control unit 20.

[0061] As one example, the receiving device according to the embodiment of the present disclosure may include first combining circuit 15, second combining circuit 16, and third combining circuit 17 on a single substrate. As another example, the received signals may be analog-to-digital converted, and the control unit 20 may generate a combined signal. In particular, the received signals generated by antenna elements 11 are amplified by low-noise amplifier 12, have their phases adjusted by phase shifter 13, have their amplitudes adjusted by gain adjuster 14, are converted into digital received signals by an analog-to-digital converter, and are transmitted to control unit 20. The control unit 20 combines the received digital received signals to generate a combined signal.

[0062] The above hardware configuration is one example, and can be changed and modified as desired. As another example of the hardware configuration, a modified hardware configuration of the control unit 20 provided in the receiving device 1 is shown in FIG. 7. The control unit 20 may be realized by a processing circuit 84, as shown in FIG. 7. The processing circuit 84 provided in the control unit 20 shown in FIG. 7 is connected to the antenna unit 10 via an interface circuit 85. Similar modifications can also be applied to the control units 20 provided in the receiving devices 2 and 3.

[0063] When the processing circuitry 84 is dedicated hardware, the processing circuitry 84 includes, for example, a single circuit, a composite circuit, a processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. Each unit of the control unit 20 may be realized by an individual processing circuit 84, or each unit of the control unit 20 may be realized by a common processing circuit 84.

[0064] Some of the functions of the control unit 20 may be realized by dedicated hardware, and other parts may be realized by software or firmware. For example, in the control unit 20, the amplitude detection unit 21 and the phase detection unit 23 may be realized by a processing circuit 84 shown in Fig. 7, and the gain suppression amount determination unit 22 and the phase adjustment amount determination unit 24 may be realized by a processor 81 shown in Fig. 2 reading and executing a program stored in a memory 82. Furthermore, all of the functions of the control unit 20 may be realized by software or firmware.

[0065] Various aspects of the present disclosure are summarized below as appendices. (Supplementary Note 1) A radio wave receiving system comprising: a plurality of antenna elements that receive radio waves including a primary polarization component and a cross polarization component that crosses the primary polarization component, and generate a first reception signal based on the primary polarization component and a second reception signal based on the cross polarization component; a plurality of second phase shifters that are provided corresponding to the antenna elements and that adjust the phase of the second reception signal generated by the corresponding antenna element based on a predetermined phase adjustment amount; a plurality of second gain adjusters that are provided corresponding to the antenna elements and that adjust the amplitude of the second reception signal generated by the corresponding antenna element based on a predetermined gain suppression amount; a first combining circuit that combines the plurality of first reception signals to generate a first combined signal; a second combining circuit that combines the plurality of second reception signals that have been phase-adjusted by the second phase shifters and amplitude-adjusted by the second gain adjusters to generate a second combined signal; and a third combining circuit that combines the first combined signal and the second combined signal, wherein the predetermined gain suppression amount is a gain suppression amount that brings the amplitude of the second combined signal closer to the amplitude of the cross polarization component included in the first combined signal, a receiving device according to claim 1, further comprising a low-noise amplifier that amplifies the first received signal or the second received signal, and the second gain adjuster is a variable amplifier that can adjust the gain of the second received signal. (Supplementary Note 3) The receiving device according to claim 1, further comprising: an antenna element that receives the radio wave, which is circularly polarized, and outputs a vertically polarized wave including a vertical component of the first received signal and a vertical component of the second received signal, and a horizontally polarized wave including a horizontal component of the first received signal and a horizontal component of the second received signal; two second phase shifters are provided corresponding to each of the antenna elements, and adjust the phase of the second received signal included in the vertically polarized wave or the horizontally polarized wave; and two second gain adjusters are provided corresponding to each of the antenna elements, and adjust the amplitude of the second received signal included in the vertically polarized wave or the horizontally polarized wave.(Supplementary Note 4) A receiving device comprising: a plurality of antenna elements that receive radio waves including a primary polarization component and a cross polarization component that crosses the primary polarization component, and generate a first received signal based on the primary polarization component and a second received signal based on the cross polarization component; a first combining circuit that combines a plurality of the first received signals to generate a first combined signal; a second combining circuit that combines a plurality of the second received signals to generate a second combined signal; a third gain adjuster that adjusts the amplitude of the second combined signal based on a gain suppression amount that brings the amplitude of the second combined signal closer to the amplitude of the cross polarization component included in the first combined signal; a third phase shifter that adjusts the phase of the second combined signal based on a phase adjustment amount that makes the phase of the second combined signal opposite the phase of the cross polarization component included in the first combined signal; and a third combining circuit that combines the first combined signal and the second combined signal adjusted by the third gain adjuster and the third phase shifter. (Supplementary Note 5) The receiving device according to any one of Supplements 1 to 4, further comprising: an amplitude detection unit that detects the amplitudes of the first combined signal and the second combined signal, a phase detection unit that detects the phases of the first combined signal and the second combined signal, a gain suppression amount determination unit that calculates the gain suppression amount, and a phase adjustment amount determination unit that calculates the phase adjustment amount. (Supplementary Note 6) The receiving device according to any one of Supplements 1 to 5, wherein the gain suppression amount is within a gain target range of ±1 dB with respect to a gain target value determined by a difference between the amplitude of a cross polarization component included in the first combined signal and the amplitude of the second combined signal. (Supplementary Note 7) The receiving device according to any one of Supplements 1 to 6, wherein the phase adjustment amount is within a phase target range of ±15% with respect to a phase target value that makes the phase of the second combined signal opposite to the phase of the cross polarization component included in the first combined signal. (Supplementary Note 8) The receiving device according to any one of Supplements 1 to 7, wherein the gain suppression amount and the phase adjustment amount are determined before operation of the receiving device is started.

[0066] The present disclosure allows various embodiments and modifications without departing from the broad spirit and scope of the present disclosure. Furthermore, the above-described embodiments are intended to illustrate the present disclosure and do not limit the scope of the present disclosure. That is, the scope of the present disclosure is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and the meaning of equivalent disclosures are considered to be within the scope of the present disclosure.

[0067] This application is based on Japanese Patent Application No. 2024-148652, filed on August 30, 2024. The entire specification, claims, and drawings of Japanese Patent Application No. 2024-148652 are incorporated herein by reference.

[0068] 1, 2, 3 receiving device, 10 antenna unit, 11 antenna element, 12, 12a, 12b, 121, 122 low noise amplifier, 13a, 131a, 132a first phase shifter, 13b, 131b, 132b second phase shifter, 14a, 141a, 142a first gain adjuster, 14b, 141b, 142b second gain adjuster, 15 first combining circuit, 16 second combining circuit, 17 third combining circuit, 18 third gain adjuster, 19 third phase shifter, 20 control unit, 21 amplitude detection unit, 22 gain suppression amount determination unit, 23 phase detection unit, 24 phase adjustment amount determination unit, 80 bus, 81 processor, 82 memory, 83 interface, 84 processing circuit, 85 interface circuit.

Claims

1. A radio wave receiving system comprising: a plurality of antenna elements that receive radio waves including a primary polarization component and a cross polarization component that crosses the primary polarization component, and generate a first reception signal based on the primary polarization component and a second reception signal based on the cross polarization component; a plurality of second phase shifters that are associated with the antenna elements and adjust the phase of the second reception signal generated by the corresponding antenna element based on a predetermined phase adjustment amount; a plurality of second gain adjusters that are associated with the antenna elements and adjust the amplitude of the second reception signal generated by the corresponding antenna element based on a predetermined gain suppression amount; a first combining circuit that combines the plurality of first reception signals to generate a first combined signal; a second combining circuit that combines the plurality of second reception signals that have been phase-adjusted by the second phase shifters and amplitude-adjusted by the second gain adjusters to generate a second combined signal; and a third combining circuit that combines the first combined signal and the second combined signal, wherein the predetermined gain suppression amount is a gain suppression amount that brings the amplitude of the second combined signal closer to the amplitude of the cross polarization component included in the first combined signal, The receiving device, wherein the predetermined phase adjustment amount is a phase adjustment amount that makes the phase of the second combined signal an opposite phase to the phase of a cross polarization component included in the first combined signal.

2. The receiving device according to claim 1, further comprising a low noise amplifier that amplifies the first received signal or the second received signal, and the second gain adjuster is a variable amplifier that is capable of adjusting the gain of the second composite signal.

3. The receiving device described in claim 1 or 2, wherein the antenna elements receive the radio waves which are circularly polarized and output vertically polarized waves containing a vertical component of the first received signal and a vertical component of the second received signal, and horizontally polarized waves containing a horizontal component of the first received signal and a horizontal component of the second received signal; the second phase shifters are provided in pairs corresponding to each of the antenna elements and adjust the phase of the second received signal contained in the vertically polarized waves or the horizontally polarized waves; and the second gain adjusters are provided in pairs corresponding to each of the antenna elements and adjust the amplitude of the second received signal contained in the vertically polarized waves or the horizontally polarized waves.

4. A receiving device comprising: a plurality of antenna elements that receive radio waves including a primary polarization component and a cross polarization component that crosses the primary polarization component, and generate a first received signal based on the primary polarization component and a second received signal based on the cross polarization component; a first combining circuit that combines a plurality of the first received signals to generate a first combined signal; a second combining circuit that combines a plurality of the second received signals to generate a second combined signal; a third gain adjuster that adjusts the amplitude of the second combined signal based on a gain suppression amount that brings the amplitude of the second combined signal closer to the amplitude of the cross polarization component included in the first combined signal; a third phase shifter that adjusts the phase of the second combined signal based on a phase adjustment amount that makes the phase of the second combined signal opposite the phase of the cross polarization component included in the first combined signal; and a third combining circuit that combines the first combined signal and the second combined signal adjusted by the third gain adjuster and the third phase shifter.

5. The receiving device described in any one of claims 1 to 4, further comprising: an amplitude detection unit that detects the amplitudes of the first combined signal and the second combined signal, respectively; a phase detection unit that detects the phases of the first combined signal and the second combined signal, respectively; a gain suppression amount determination unit that determines the gain suppression amount; and a phase adjustment amount determination unit that determines the phase adjustment amount.

6. A receiving device described in any one of claims 1 to 5, wherein the amount of gain suppression is within a gain target range of ±1 dB with respect to a gain target value determined by the difference between the amplitude of the cross-polarization component contained in the first composite signal and the amplitude of the second composite signal.

7. A receiving device according to any one of claims 1 to 6, wherein the phase adjustment amount is within a phase target range of ±15% of a phase target value that makes the phase of the second composite signal the opposite phase to the phase of the cross-polarized component contained in the first composite signal.

8. The receiving device according to any one of claims 1 to 7, wherein the amount of gain suppression and the amount of phase adjustment are determined before operation of the receiving device begins.

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