Reception directivity control device and method for manufacturing same

Abstract

One aspect of the present invention relates to a reception directivity control device comprising: at least one light source; a first phase weighting unit that applies phase weighting in a first direction to light from at least one light source; a plurality of reception antennas that receive wireless signals; a plurality of electro-optical conversion units that perform electro-optical conversion on the wireless signals received by the plurality of reception antennas on the basis of a signal to which the first phase weighting unit has applied the phase weighting in the first direction; a second phase weighting unit that applies phase weighting in a second direction to the signals on which the plurality of electro-optical conversion unit has performed the electro-optical conversion; and a demodulation unit that demodulates the signals to which the second phase weighting unit has applied the phase weighting in the second direction, wherein the sum of the lengths of input-side lines from the first phase weighting unit to the plurality of electro-optical conversion units is equal to the sum of the lengths of output-side lines from the plurality of electro-optical conversion units to the second phase weighting unit.

Description

Receiving directivity control device and manufacturing method thereof

[0001] The present invention relates to a receiving directivity control device and a manufacturing method thereof.

[0002] Millimeter-wave and higher frequency bands are increasingly being utilized as a means of achieving faster and larger capacity wireless communications. The spatial propagation loss of radio waves increases with increasing frequency. For example, free-space propagation loss increases in proportion to the square of the frequency. Therefore, receiving antennas with high gain are often used in these high-frequency bands. High-gain receiving antennas have high directivity. Therefore, it is necessary to align the beam direction with the remote station in wireless communications. When the remote station's direction is dynamic, a means for dynamically controlling the beam direction, i.e., beam steering, is required. Furthermore, beam steering in receiving antennas is necessary not only for wireless communications but also for applications such as radar, imaging, and wireless power transmission.

[0003] Beam steering methods include mechanically controlling the direction of the receiving antenna, or using movable lenses or reflectors to refract or reflect the radio waves emitted from the receiving antenna. Phased array antennas are also widely used because they do not use any mechanically moving parts, making them highly durable and adaptable to movement, and suitable for making receiving antennas smaller and lighter.

[0004] A phased array antenna performs electronic beam steering by controlling (called weighting) the phase and amplitude of the RF (Radio Frequency) signal supplied to each receiving antenna using means such as variable delay circuits, variable attenuator circuits, and digital signal processing connected to multiple receiving antennas arranged on a line or surface.

[0005] 2. Description of the Related Art Phased array antennas that perform weighting using analog circuits are widely used in fifth generation mobile communication systems and millimeter wave band wireless LAN (Local Area Network) systems that use millimeter wave bands.

[0006] As the use of high-frequency bands expands, even higher receiving antenna gains are required. Therefore, it is expected that phased array antennas that weight even more receiving antennas will be needed. For example, Non-Patent Document 1 discloses a configuration method for a 256-element phased array antenna to be used in a fifth-generation mobile communication base station in the 28 GHz band. For sixth-generation mobile communications aiming to provide even higher transmission rates, the use of the 300 GHz band (also known as the terahertz band) is being considered. If the radio frequency becomes about 10 times higher than the 28 GHz band, the free-space propagation loss will be 100 times higher (in other words, the free-space propagation loss will increase by 20 dB). Taking this into consideration, it is expected that, for example, more than 10,000 receiving antennas will be required to compensate for the base station's receiving antenna gain.

[0007] To minimize power loss to the receiving antenna, the RF transmission line feeding power from the phase shifter circuit to the receiving antenna must be as short as possible. Therefore, in high-frequency phased array antennas, particularly those in the millimeter-wave band, the phase shifter circuits are typically arranged near each receiving antenna. However, as the radio frequency increases, the spacing between receiving antennas becomes increasingly narrow, making it difficult to arrange multiple phase shifter circuits at the same spacing as the receiving antennas. For example, for a radio frequency of 300 GHz, the free-space wavelength is 1 mm, so the spacing between receiving antennas is typically half the wavelength, or 0.5 mm. Furthermore, to configure a circuit that forms multiple beams (a multi-beam forming circuit), the same number of phase shifters as the number of beams must be arranged in parallel, further increasing the difficulty.

[0008] Therefore, the application of optical circuits that can implement low-loss waveguides in a small size has been considered, and for example, Non-Patent Document 2 proposes a method in which signals are converted into light and then weighted using an optical circuit. This increases the possibility of configuring multi-element and two-dimensional weighting circuits, but since the number of components in the weighting circuit increases with the number of receiving antennas, it is necessary to suppress the increase in the number of components as much as possible while dealing with an increase in the number of receiving antennas.

[0009] The following means are known as existing technologies for implementing weighting using optical circuits. Patent Document 1 discloses an optically controlled array antenna device that uses a wavelength dispersion line to control two-dimensional multibeams. For example, FIG. 10 of Patent Document 1 shows the device configuration, and FIG. 11 of Patent Document 1 discloses the configuration of a device that supports both transmission and reception. In Patent Document 1, a wavelength tunable light source and a line using a waveguide with large wavelength dispersion are used to provide phase tilt in the horizontal and vertical planes, but the number of one-dimensional phase shift circuits ("EL_1 to EL_P" and "AZ_1" to "AZ_N" in FIG. 10 of Patent Document 1) required is large depending on the number of receiving antennas in the vertical direction and the number of receiving antennas in the horizontal direction.

[0010] Patent Document 2 also discloses a method for two-dimensional beam control using a wavelength-tunable light source and wavelength dispersion lines. For example, FIG. 12 of Patent Document 2 shows the configuration of the device. In FIG. 12 of Patent Document 2, light from a wavelength-tunable light source 42 (e.g., wavelength λV) is split into the number of vertical elements (five splits in FIG. 12 of Patent Document 2), a phase tilt in the vertical plane is imparted by a first array of wavelength dispersion lines, and each is then converted back into an electrical signal train by a photodiode. Next, in FIG. 12 of Patent Document 2, light from a wavelength-tunable light source 84 (e.g., wavelength λH) is split into the number of vertical elements (five splits in FIG. 12 of Patent Document 2), each of which is modulated with the aforementioned electrical signal train to generate an optical signal train. Each optical signal is split into the number of horizontal elements (13 splits in FIG. 12 of Patent Document 2), and a phase tilt in the horizontal plane is imparted to these optical signal trains by a second array of wavelength dispersion lines (five of which are provided in FIG. 12 of Patent Document 2). By the above operation, vertical scanning is controlled by λV and horizontal scanning is controlled by λH. Figure 13 of Patent Document 2 shows the operation during reception. In Figure 13 of Patent Document 2, a local oscillator signal (LO signal) with a phase tilt is generated by an optical circuit, and this is mixed with a received RF signal also having a phase tilt to generate an IF signal, and only the received signals in the desired beam direction are in-phase combined in an IF band combiner to obtain the received signal.

[0011] 12 of Patent Document 2 shows only the configuration of a one-dimensional array, but if an apparatus is configured to use two wavelength-tunable light sources and input light with a two-dimensional phase gradient to a two-dimensionally arranged photomixer array, similar to the configuration shown in Patent Document 2, and RF band CW (Continuous Wave) is input to optical modulator 46, it is possible to control the receiving directivity of a two-dimensional array antenna. As disclosed in Patent Document 2, the second wavelength dispersion line array is composed of lines (13 lines) corresponding to the number of horizontal receiving antennas, and it is necessary to prepare lines corresponding to the number of vertical receiving antennas (5 lines). When configuring a large-scale two-dimensional array antenna, there are problems such as a large number of required lines, a large circuit scale, and ultimately large circuit size (area and volume). Although Patent Document 2 does not explicitly state a method for controlling reception of multiple beams, it is necessary to prepare multiplexers at IF (Intermediate Frequency) equal to the number of beams, which poses a problem of increasing the size of the device.

[0012] Considering the need for a low-profile device configuration, miniaturization of the device, and mass production using a printed circuit manufacturing process, it is desirable to have a configuration of the reception directivity control device that does not require a three-dimensional structure.

[0013] Japanese Patent Application Laid-Open No. 2004-023400 U.S. Patent No. 6,337,660

[0014] H. Watanabe, S. Uga, H. Nakamizo, T. Tsutsumi, S. Shinjo, and Y. Kuriyama, "Millimeter-Wave Receiving Antenna and RF Front-End Technology for 5th Generation Mobile Communication Base Stations," IEICE Communications Society Magazine, 2020, Vol. 14, No. 3, pp. 222-231. C. Tsokos et al., "Analysis of a Multibeam Optical Beamforming Network Based on Glass Matrix Architecture," in Journal of Lightwave Technology, Vol. 36, No. 16, pp. 3354-3372, 15 Aug. 15, 2018.

[0015] In conventional optically controlled array antennas, if the feeder lines connecting the electro-optical converters and phase-shift circuits provided for each receiving antenna are not the same length, the difference in phase rotation that occurs due to the difference in the feeder lines could affect the phase weighting of the array antenna.

[0016] In view of the above circumstances, an object of the present invention is to provide a receiving directivity control device that can prevent a difference in phase rotation, which occurs when the input line and the output line are not of equal length, from affecting the phase weighting of an array antenna, and a method for manufacturing the same.

[0017] One aspect of the present invention is a receiving directivity control device comprising at least one light source, a first phase weighting unit that applies a phase weighting in a first direction to light from the at least one light source, a plurality of receiving antennas that receive wireless signals, a plurality of electro-optical conversion units that perform electro-optical conversion on the wireless signals received by the plurality of receiving antennas based on the signals to which the first phase weighting unit has applied a phase weighting in the first direction, a second phase weighting unit that applies a phase weighting in a second direction to the signals to which the plurality of electro-optical conversion units has applied a phase weighting in the second direction, and a demodulation unit that demodulates the signals to which the second phase weighting unit has applied a phase weighting in the second direction, wherein the total length of the input side lines from the first phase weighting unit to the plurality of electro-optical conversion units is equal to the total length of the output side lines from the plurality of electro-optical conversion units to the second phase weighting unit.

[0018] Another aspect of the present invention is a method for manufacturing a reception directivity control device that includes at least one light source, a first phase weighting unit that applies phase weighting in a first direction to light from the at least one light source, a plurality of receiving antennas that receive wireless signals, a plurality of electro-optical conversion units that perform electro-optical conversion on the wireless signals received by the plurality of receiving antennas based on the signals to which the first phase weighting unit has applied phase weighting in the first direction, a second phase weighting unit that applies phase weighting in a second direction to the signals to which the plurality of electro-optical conversion units has applied phase weighting in the second direction, and a demodulation unit that demodulates the signals to which the second phase weighting unit has applied phase weighting in the second direction, wherein the method for manufacturing a reception directivity control device is configured so that the total length of the input side lines from the first phase weighting unit to the plurality of electro-optical conversion units is equal to the total length of the output side lines from the plurality of electro-optical conversion units to the second phase weighting unit.

[0019] According to the present invention, it is possible to provide a receiving directivity control device that can prevent the difference in phase rotation that occurs when the input line and the output line are not of equal length from affecting the phase weighting of an array antenna, and a method for manufacturing the same.

[0020] FIG. 11 is a schematic configuration diagram of a reception directivity control device related to the reception directivity control device of the present invention. FIG. 12 is a diagram explaining the directions of first to fourth beams of the reception directivity control device of FIG. 1. FIG. 13 is a schematic configuration diagram of another reception directivity control device related to the reception directivity control device of the present invention. FIG. 14 is a schematic configuration diagram of a reception directivity control device according to a first embodiment of the present invention. FIG. 15 is a table explaining the phases of optical signals output from receiving elements until they are input to a horizontal weighting circuit. FIG. 16 is a schematic configuration diagram of a reception directivity control device according to a second embodiment of the present invention. FIG. 17 is a table showing the phases of each signal related to the first row receiving elements. FIG. 18 is a table showing the phases of each signal related to the second row receiving elements.

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The embodiment described below is merely an example, and the embodiment to which the present invention is applied is not limited to the following embodiment. First, the operation of the reception directivity control device related to the reception directivity control device of the present invention and the problem of phase rotation of the power feed line will be described.

[0022] FIG. 1 is a schematic diagram of a receiving directivity control device related to the receiving directivity control device of the present invention. In the receiving directivity control device 100A shown in FIG. 1, the array antenna is configured with receiving antennas (i.e., receiving antennas 1A-1-1, 1A-1-2, 1A-2-1, and 1A-2-2) consisting of two elements in the vertical direction and two elements in the horizontal direction (i.e., a total of four elements). The receiving antennas 1A-1-1 and 1A-1-2 form the first row of array antennas. The receiving antennas 1A-2-1 and 1A-2-2 form the second row of array antennas. Electro-optical converters (i.e., optical modulators) 8A-1-1, 8A-1-2, 8A-2-1, and 8A-2-2 are connected to the receiving antennas 1A-1-1, 1A-1-2, 1A-2-1, and 1A-2-2, respectively. The RF (Radio Frequency) signals received by the receiving antennas 1A-1-1, 1A-1-2, 1A-2-1, and 1A-2-2 are used to modulate the light of the light source 3A, thereby converting the received RF signals into optical signals.

[0023] The reception directivity control device 100A shown in FIG. 1 is capable of selecting and receiving any one of the first beam B01, the second beam B02, the third beam B03, and the fourth beam B04 in four directions.

[0024] Figure 2 is a diagram explaining the directions of the first to fourth beams B01, B02, B03, and B04 of the reception directivity control device 100A of Figure 1. When viewing space from the array antenna (to the left on the paper in Figure 1), the beam in the upper left direction is the first beam B01, the beam in the upper right direction is the second beam B02, the beam in the lower left direction is the third beam B03, and the beam in the lower right direction is the fourth beam B04. Here, we will first explain the operation when receiving the second beam B02.

[0025] First, the vertical plane scanning process will be described. There is a predetermined phase difference φ between adjacent receiving antennas in the vertical plane direction, specifically, between the RF signal received by receiving antenna 1A-1-1 and the RF signal received by receiving antenna 1A-2-1, due to the difference in arrival time of the radio wave (RF signal) arriving from above from space to each receiving antenna. Ｖ (phase tilt). Hereinafter, this phase tilt will be referred to as the vertical phase tilt. The phase difference between the RF signal received by the receiving antenna 1A-1-2 and the RF signal received by the receiving antenna 1A-2-2 is also equal to the vertical phase tilt. Here, the number of receiving antennas in the vertical plane direction is two elements, but even in the case of three or more elements, the phase difference between the RF signals received by adjacent receiving antennas is uniformly φ Ｖ This becomes:

[0026] The RF signal received by the receiving antenna 1A-1-1 is where ω ＲＦ is the frequency of the RF signal.

[0027] On the other hand, as described above, the RF signal received by the receiving antenna 1A-2-1 is φ Ｖ Since it is delayed by It is expressed as:

[0028] The CW light output from the light source 3A is input to an input terminal 401A of a vertical scanning switching circuit 4A, processed by the vertical scanning switching circuit 4A, output from output terminals 402A and 403A of the vertical scanning switching circuit 4A, and input to input terminals 501A and 502A of a vertical weighting circuit 5A. At this time, the input terminals 501A and 502A are designated by a vertical scanning instruction circuit 6A controlling the vertical scanning switching circuit 4A according to the direction of the beam to be received in the vertical plane (i.e., the elevation angle of the beam). When the beam direction in the vertical plane is upward, i.e., when the first beam B01 or the second beam B02 is to be received, the input terminal 501A is designated. Conversely, when the beam direction in the vertical plane is downward, i.e., when the third beam B03 or the fourth beam B04 is to be received, the input terminal 502A is designated.

[0029] The CW light output from the two output terminals 503A and 504A of the vertical weighting circuit 5A has a phase tilt that is (-1) times the vertical phase tilt. The CW light output from the output terminal 503A is split into two by a splitter 7A-1, and each is input to an electro-optical converter 8A-1-1 and an electro-optical converter 8A-1-2 with the same phase. Similarly, the CW light output from the output terminal 504A of the vertical weighting circuit 5A has a phase φ different from that of the CW light output from the output terminal 503A. Ｖ The signal is advanced by 1.0 volts, and is split into two by splitter 7A-2, and each is input to electro-optical converter 8A-2-1 and electro-optical converter 8A-2-2 with the same phase.

[0030] The CW light input to the electro-optical converter 8A-1-1 is where ω ｃ is the frequency of the CW light from the light source 3A.

[0031] Furthermore, the CW light input to the electro-optical converter 8A-2-1 has a phase difference of φ from the CW light input to the electro-optical converter 8A-1-1 due to the action of the vertical scanning switching circuit 4A. Ｖ Because it is only progressing, In this way, the CW light input to the electro-optical converter 8A-2-1 is φ Ｖ As described above, the RF signal input to the electro-optical converter 8A-2-1 is ahead of the RF signal input to the electro-optical converter 8A-1-1 by φ. Ｖ Therefore, the upper sideband component (so-called USB (Upper Side Band) component) of the optical signal output from the electro-optical converter 8A-1-1 is delayed by an intensity modulation (amplitude modulation) signal {1+2A cos(ω ＲＦ t)}cos(ω ｃ t) and the USB components are extracted from it. Here, A is a constant representing the amplitude.

[0032] On the other hand, the output of the electro-optical converter 8A-2-1 is Therefore, the USB components of the two signals are combined in phase in the combiner 9A-1.

[0033] Similarly, the RF signals received by receiving antennas 1A-1-2 and 1A-2-2 are converted into optical signals by electro-optical converters 8A-1-2 and 8A-2-2, respectively, and the USB components of these two optical signals are combined in phase by multiplexer 9A-2.

[0034] Next, the horizontal plane scanning process will be described. The direction of the second beam B02 is to the right in the horizontal plane, but there is a predetermined phase difference φ between the RF signals received by adjacent receiving antennas in the horizontal plane, specifically, the RF signals received by the receiving antennas 1A-1-1 and 1A-1-2, due to the difference in arrival time of radio waves arriving from the right direction from space to each receiving antenna. Ｈ Hereinafter, this phase tilt will be referred to as the horizontal phase tilt. There is also a phase difference φ between the RF signal received by the receiving antenna 1A-2-1 and the RF signal received by the receiving antenna 1A-2-2. Ｈ There is.

[0035] As described above, the USB component of the optical signal output from the electro-optical converter 8A-1-1 is is.

[0036] On the other hand, the electro-optical converter 8A-1-2 receives a signal having a phase φ different from the RF signal input to the electro-optical converter 8A-1-1. Ｈ An RF signal advanced by 1 / 2 and a CW light in phase with the CW light input to the electro-optical converter 8A-1-1 are input. Therefore, the USB component of the optical signal output from the electro-optical converter 8A-1-2 is It is expressed as:

[0037] In this way, the phase difference between the optical signal output from the electro-optical converter 8A-1-1 and the optical signal output from the electro-optical converter 8A-1-2 is equal to the horizontal phase tilt.

[0038] As described above, the USB component of the optical signal output from the electro-optical converter 8A-2-1 is The electro-optical converter 8A-2-2 receives an RF signal having a phase φ different from that of the RF signal input to the electro-optical converter 8A-2-1. ＨThe RF signal advanced by 1 / 2 and the CW light in phase with the CW light input to the electro-optical converter 8A-2-1 are input. Therefore, the USB component of the optical signal output from the electro-optical converter 8A-2-2 is The phase difference between the optical signal output from the electro-optical converter 8A-2-1 and the optical signal output from the electro-optical converter 8A-2-2 is equal to the horizontal phase tilt.

[0039] In the multiplexer 9A-2, the USB component A cos{(ω ｃ +ω ＲＦ ) t} and the USB component A cos{(ω ｃ +ω ＲＦ )t} are in-phase combined. In addition, the multiplexer 9A-2 combines the USB component A cos{(ω ｃ +ω ＲＦ ) t + φ Ｈ} and the USB component A cos{(ω ｃ +ω ＲＦ ) t + φ Ｈ} are synthesized in phase.

[0040] Therefore, the phase difference between the optical signals output from multiplexers 9A-1 and 9A-2 is equal to the horizontal phase tilt. These optical signals are input to input terminals 101A and 102A of horizontal weighting circuit 10A, respectively.

[0041] These two signals input to the horizontal weighting circuit 10A are combined in phase only at the output terminal (here, output terminal 104A) corresponding to the horizontal direction of the beam (here, the second beam B02, rightward), so that a strong signal is output, whereas at the other output terminal (here, output terminal 103A), the signals are not combined in phase and therefore are not output at a sufficient level.

[0042] The horizontal scanning instruction circuit 11A controls the horizontal scanning switching circuit 12A so that only the output of the output terminal 104A of the horizontal weighting circuit 10A is output from the received signal output terminal 13A via the output terminal 123A. When the beam direction in the horizontal plane is to the right, the output terminal 104A is selected, and when the beam direction in the horizontal plane is to the left, the output terminal 103A is selected.

[0043] In this way, the reception directivity control device 100A performs an operation to receive only the second beam B02. When receiving other beams (first beam B01, third beam B03, and fourth beam B04), the vertical scanning instruction circuit 6A and the horizontal scanning instruction circuit 11A appropriately control the vertical scanning switching circuit 4A and the horizontal scanning switching circuit 12A, respectively, based on instructions from the beam direction selection circuit 14A.

[0044] As described above, by using the receiving directivity control device 100A, it is possible to control the directivity of the receiving beam in two directions, the horizontal plane and the vertical plane. However, the CW light output from the light source 3A must be input to each of the electro-optical converters 8A-1-1, 8A-1-2, 8A-2-1, and 8A-2-2 at a predetermined phase. Furthermore, the optical signals output from the electro-optical converters 8A-1-1, 8A-1-2, 8A-2-1, and 8A-2-2 must be input to each of the multiplexers 9A-1 and 9A-2 at a predetermined phase. However, since the vertical weighting circuit 5A, distributors 7A-1, 7A-2, electro-optical converters 8A-1-1, 8A-1-2, 8A-2-1, 8A-2-2, multiplexers 9A-1, 9A-2, and horizontal weighting circuit 10A are arranged at large intervals relative to the wavelength of the CW light or optical signal, it is necessary to take into consideration the phase rotation in the transmission line of the optical signal connecting these, i.e., the power supply line.

[0045] For example, signals output from light source 3A and passing through vertical weighting circuit 5A and distributor 7A-1, each of which has the same phase, need to be input to electro-optical converters 8A-1-1 and 8A-1-2. However, if the power feed lines are wired as shown in FIG. 1, the line lengths from distributor 7A-1 to each electro-optical converter are different, making it difficult to feed power in the same phase. Furthermore, while the outputs of electro-optical converters 8A-1-1 and 8A-2-1 are in phase, if the line lengths from these electro-optical converters to multiplexer 9A-1 are not equal, in-phase combining will not be possible. As explained for reception directivity control device 100A, when there are two electro-optical converters, the line lengths from the electro-optical converters to multiplexer 9A-1 can be made equal, as shown in FIG. 1. However, when there are three or more electro-optical converters, some ingenuity is required.

[0046] Figure 3 is a schematic diagram of another receive directivity control device related to the receive directivity control device of the present invention. The receive directivity control device 100B shown in Figure 3 has a configuration similar to the receive directivity control device 100A described in Figure 1, and includes receive antennas 1B-1-1, 1B-1-2, 1B-2-1, and 1B-2-2, a light source 3B, a vertical weighting circuit 5B, a vertical scanning instruction circuit 6B, distributors 7B-1 and 7B-2, electro-optical converters 8B-1-1, 8B-1-2, 8B-2-1, and 8B-2-2, multiplexers 9B-1 and 9B-2, a horizontal weighting circuit 10B, a horizontal scanning instruction circuit 11B, and a beam direction selection circuit 14B. The receive directivity control device 100B also includes delay lines 15B-1, 15B-2, 15B-3, and 15B-4 for equalizing the lengths of the signals, and a demodulator 16B.

[0047] In Figure 3, delay lines 15B-1 and 15B-2 are inserted to equalize the line lengths from the distributors 7B-1 and 7B-2 to the subsequent electro-optical converters 8B-1-1, 8B-1-2, 8B-2-1, and 8B-2-2. Furthermore, in Figure 3, delay lines 15B-3 and 15B-4 are inserted to equalize the line lengths from the electro-optical converters 8B-1-1, 8B-1-2, 8B-2-1, and 8B-2-2 to the subsequent multiplexers 9B-1 and 9B-2. As shown in Figure 3, the number of delay lines that need to be inserted to equalize the lengths of each partial line is (number of horizontal elements - 1) x (number of vertical elements) + (number of vertical elements - 1) x (number of horizontal elements). 3, the delay lines (i.e., delay lines 15B-1, 15B-2, 15B-3, and 15B-4) occupy a large area, which may result in a large circuit implementation size. Also, the delay lines may attenuate the optical signal, which may reduce the signal-to-noise ratio and degrade the signal quality.

[0048] It is also possible to configure the power supply circuit three-dimensionally to achieve equal lengths, but manufacturing a three-dimensional optical fiber path is extremely difficult, so it is desirable to configure it as a planar circuit that can be manufactured using a highly reproducible production method and a printing process suitable for mass production.

[0049] [First Embodiment] Next, a first embodiment of the present invention will be described. FIG. 4 is a schematic configuration diagram of a reception directivity control device 100C according to the first embodiment of the present invention. The reception directivity control device 100C shown in FIG. 4 is a reception directivity control device using a 4×4 array antenna with four elements arranged vertically and four elements horizontally. Each of the 16 reception elements 17C-1-1 to 17C-1-16 arranged in a grid pattern includes a reception antenna and an electro-optical converter. In other words, FIG. 4 conceptually illustrates reception element 17C-1-2 including reception antenna 1C-1-2 and electro-optical converter 8C-1-2. However, like reception element 17C-1-2, the other reception elements 17C-1-1, 17C-2 to 17C-1-16 also include a reception antenna and an electro-optical converter.

[0050] The RF signals received by the receiving antennas provided in the receiving elements 17C-1-1 to 17C-1-16 are converted into optical signals and then subjected to phase shift processing, thereby controlling the receiving directivity. CW light is input to the receiving elements 17C-1-1 to 17C-1-16, and the input CW light is modulated by the RF signal received by the receiving antenna in an electrical-to-optical converter, and output from the receiving elements 17C-1-1 to 17C-1-16. The electrical-to-optical converters provided in the receiving elements 17C-1-1 to 17C-1-16 may be provided with RF amplifiers (not shown) that amplify the level of the RF signals supplied from the receiving antennas.

[0051] The 16 receiving elements 17C-1-1 to 17C-1-16 constitute a two-dimensional antenna array as described above, and are therefore arranged in a 4-row by 4-column grid as shown in Fig. 4. The CW light output from each output terminal 501C to 504C of the vertical weighting circuit 5C passes through delay lines 15C-1 to 15C-4 provided in each row, and is then sequentially distributed by distributors 7C-1-1, 7C-1-2, 7C-1-3, 7C-2-1, 7C-2-2, 7C-2-3, 7C-3-1, 7C-3-2, and 7C-3-3 provided for the receiving elements 17C-1-1 to 17C-1-16, and input to each of the receiving elements 17C-1-1 to 17C-1-16 arranged in the row direction. The CW light output from input terminals 101C, 102C, 103C, and 104C of the horizontal weighting circuit 10C is input to distributors 7C-1-1, 7C-2-1, 7C-3-1, and 7C-4-1 via delay lines 15C-1, 15C-2, 15C-3, and 15C-4. The CW light input to distributors 7C-1-1, 7C-2-1, 7C-3-1, and 7C-4-1 is split into two, one of which is input to receiving elements 17C-1-1, 17C-2-1, 17C-3-1, and 17C-4-1, and the other of which is input to distributors 7C-1-2, 7C-2-2, 7C-3-2, and 7C-4-2. Similarly, the light input to the distributors 7C-1-2, 7C-2-2, 7C-3-2, and 7C-4-2 is split into two, one of which is input to the receiving elements 17C-1-2, 17C-2-2, 17C-3-2, and 17C-4-2, and the other is input to the distributors 7C-1-3, 7C-2-3, 7C-3-3, and 7C-4-3. The light input to the distributors 7C-1-3, 7C-2-3, 7C-3-3, and 7C-4-3 is split into two, one of which is input to the receiving elements 17C-1-3, 17C-2-3, 17C-3-3, and 17C-4-3, and the other is input to the receiving elements 17C-1-4, 17C-2-4, 17C-3-4, and 17C-4-4.

[0052] Here, n=1, 2, 3, i=1, 2, 3, 4, and the difference between the amount of phase rotation in the line from the output terminal of the distributor 7C-i-n to the input terminal of the receiving element 17C-i-n and the amount of phase rotation in the line from the output terminal of the distributor 7C-i-n to the input terminal of the receiving element 17C-i-(n+1) is expressed as L Ｈ，ｎ Let's say.

[0053] The optical signals output from each receiving element 17C-1-1 to 17C-1-16 are sequentially multiplexed by multiplexers 9C-1-1, 9C-1-2, 9C-1-3, 9C-1-4, 9C-2-1, 9C-2-2, 9C-2-3, 9C-2-4, 9C-3-1, 9C-3-2, 9C-3-3, and 9C-3-4, with the four signals belonging to each column passing through delay lines 15C-5, 15C-6, 15C-7, and 15C-8 provided in each column, and then input to the horizontal weighting circuit 10C.

[0054] Here, the flow of optical signals with respect to the receiving elements in the jth column will be explained. j is an integer between 1 and 4. The optical signal output from the receiving element 17C-1-j is input to the multiplexer 9C-1-j and multiplexed with the optical signal output from the receiving element 17C-2-j. The optical signal output from the multiplexer 9C-1-j is input to the multiplexer 9C-2-j and multiplexed with the optical signal output from the receiving element 17C-3-j. Next, the optical signal output from the multiplexer 9C-2-j is input to the multiplexer 9C-3-j and multiplexed with the optical signal output from the receiving element 17C-4-j. The optical signals output from the multiplexer 9C-3-j pass through j-th delay lines 15C-5, 15C-6, 15C-7, and 15C-8 and are input to j-th input terminals 101C, 102C, 103C, and 104C of the horizontal weighting circuit 10C.

[0055] Here, m=1, 2, 3, and the difference between the amount of phase rotation in the line from the output terminal of the receiving element 17C-m-j to the input terminal of the multiplexer 9C-m-j and the amount of phase rotation in the line from the output terminal of the receiving element 17C-(m+1)-j to the input terminal of the multiplexer 9C-m-j is defined as L Ｖ，ｍ Let's say.

[0056] The delay amount of the ith delay line 15C-1, 15C-2, 15C-3, 15C-4 through which the CW light output from the ith output terminal (i=1, 2, 3, 4) of the vertical weighting circuit 5C passes is expressed as follows: and the delay amount of the j-th delay line 15C-5, 15C-6, 15C-7, 15C-8 through which the optical signal input to the j-th input terminal (j=1, 2, 3, 4) of the horizontal weighting circuit 10C passes is set to be Here, N is the maximum value of j, that is, 4.

[0057] By configuring the reception directivity control device 100C in this way, two-dimensional scanning can be performed. The operation will be explained below. First, the phase of the optical signal output from the receiving element 17C-i-j until it is input to the horizontal weighting circuit 10C will be explained. This explanation is also shown in table form in Figure 5.

[0058] The phase of the RF signal received by the receiving antenna 1C-i-j and input to the electro-optical converter 8C-i-j has a phase gradient that depends on the horizontal and vertical directions of arrival of the radio wave, so is.

[0059] The phase of the CW light input to the electrical-to-optical converter 8C-i-j is the sum of the vertical phase tilt given by the vertical weighting circuit 5C in accordance with the in-vertical direction of the received beam based on the instruction from the vertical scanning instruction circuit 6C and the phase rotation in the line connecting the i-th row output terminal of the vertical weighting circuit to the receiving element 17C-i-j. This becomes:

[0060] The phase of the optical signal USB component output from the electrical-to-optical conversion unit 8C-i-j is the sum of the phase of the RF signal input to the electrical-to-optical conversion unit 8C-i-j and the phase of the CW light input to the electrical-to-optical conversion unit 8C-i-j, so This becomes:

[0061] Although the first embodiment uses the USB component as the sideband wave, an LSB (lower side band) component may also be used. The phase of the LSB component of the optical signal output from the electro-optical converter 8C-i-j is obtained by subtracting the phase of the RF signal input to the electro-optical converter 8C-i-j from the phase of the CW light input to the electro-optical converter 8C-i-j, so the phase tilt of the vertical weighting circuit 5C should be set to have an opposite sign to that in the first embodiment.

[0062] The phase of the USB component input to the horizontal weighting circuit 10C is the phase of the optical signal USB component output from the electro-optical conversion unit 8C-i-j plus the phase rotation in the line connecting the output terminal of the electro-optical conversion unit 8C-i-j to the j-th column input terminal of the horizontal weighting circuit 10C, so This becomes:

[0063] Here, the second and third terms of the above equation are constants that do not depend on i or j, so the phase of the optical signal output from the receiving element 17C-i-j when it is input to the j-th column input terminal of the horizontal weighting circuit 10C is given by It can be seen that:

[0064] Therefore, it can be seen that all optical signals output from the elements in the jth column are combined in phase and input to the jth column input terminal of the horizontal weighting circuit 10C. Furthermore, the four optical signals input to the four input terminals 101C, 102C, 103C, and 104C of the horizontal weighting circuit 10C have a horizontal phase tilt. Therefore, if the horizontal weighting circuit 10C performs the same weighting process on these four optical signals as that of a one-dimensional array antenna based on instructions from the horizontal scanning instruction circuit 11C, all optical signals will be combined in phase and output to the demodulator 16C. In this way, two-dimensional receiving directivity control can be achieved.

[0065] The reception directivity control device 100C according to the first embodiment includes at least one light source 3C, a vertical weighting circuit 5C (also referred to as a first phase weighting unit) that applies phase weighting in the vertical direction (also referred to as a first direction) to light from the at least one light source 3C, a plurality of reception antennas (for example, reception antennas 1C-1-2) that receive radio signals, a plurality of electro-optical conversion units (for example, electro-optical converters 8C-1-2) that perform electro-optical conversion on the radio signals received by the plurality of reception antennas based on the signals that have been subjected to vertical phase weighting by the vertical weighting circuit 5A, and The antenna includes a horizontal weighting circuit 10C (also referred to as a second phase weighting unit) that applies phase weighting in the horizontal direction (also referred to as a second direction), and a demodulator 16C (also referred to as a demodulator) that demodulates the signal that has been horizontally phase-weighted by the horizontal weighting circuit 10C, and the total length of the input lines (lines shown by thick lines in FIG. 4) from the vertical weighting circuit 5C to the multiple electro-optical converters is equal to the total length of the output lines (lines shown by dotted lines in FIG. 4) from the multiple electro-optical converters to the horizontal weighting circuit 10C. Note that the total length of the input lines from the vertical weighting circuit 5C to the multiple electro-optical converters and the total length of the output lines from the multiple electro-optical converters to the horizontal weighting circuit 10C being equal does not only mean that they are completely equal, but also means that the difference in phase rotation caused by the input lines and output lines not being of equal length has a negligible effect on the phase weighting of the array antenna.

[0066] The receive directivity control device 100C according to the first embodiment can prevent the difference in phase rotation caused by the unequal lengths of the input and output lines from affecting the phase weighting of the array antenna. Furthermore, it is not necessary to equalize the lengths of all lines connecting each element to the phase shift circuit using redundant delay lines or three-dimensional wiring, which is difficult to manufacture. Furthermore, it is possible to use a successive distribution type or successive combination type signal distribution / combining system that can be implemented in a small area, without using a batch divider or batch combiner that requires a large mounting area. Furthermore, it is possible to perform receive beam scanning for multiple elements without significantly increasing the number of circuit components. Furthermore, it is possible to provide a device that is suitable for mass production and miniaturization by significantly reducing the number of components and wiring in the beam forming circuit and feeder line.

[0067] Second Embodiment Next, a second embodiment of the present invention will be described. Fig. 6 is a schematic diagram of a reception directivity control device 100D according to the second embodiment of the present invention. The reception directivity control device 100D shown in Fig. 6 is configured with an equally spaced 4 x 4 array antenna. Note that parts of the configuration of the second embodiment that are similar to those of the first embodiment are assigned the same reference numerals, and their description will be omitted.

[0068] The reception directivity control device 100D according to the second embodiment includes a light source 3D, a vertical weighting circuit 5D (having output terminals 501D, 502D, 503D, and 504D), a vertical scanning instruction circuit 6D, distributors 7D-1-1 to 7D-4-3, multiplexers 9D-1-1 to 9D-3-4, a horizontal weighting circuit 10D (having input terminals 101D, 102D, 103D, and 104D), a horizontal scanning instruction circuit 11D, a beam direction selection circuit 14D, receiving elements 17D-1-1 to 17D-4-4, and a demodulator 16D.

[0069] Since the element spacing of an antenna array is often equal (often half the free space wavelength of the RF frequency), It is considered that in many cases, all of the values ​​L will be the same.

[0070] The receiving directivity control device 100D shown in FIG. 6 is configured as a planar circuit, and by arranging the vertical weighting circuit 5D, the horizontal weighting circuit 10D, and the receiving elements 17D-1-1 to 17D-4-4, the i-th row delay line and the j-th column delay line can be configured to have predetermined lengths.

[0071] The phases of optical signals in the second embodiment are shown using specific numerical calculations. Figure 7 shows the phases of each signal related to receiving elements 17D-1-1 to 17-1-4 in the first row. Figure 8 shows the phases of each signal related to receiving elements 17D-2-1 to 17D-2-4 in the second row. While explanations of receiving elements 17D-3-1 to 17D-3-4 in the third row and receiving elements 17D-4-1 to 17D-4-4 in the fourth row will be omitted, in each column, the optical signals output from the four elements are all combined in phase, and the four optical signals input to the four input terminals of horizontal weighting circuit 10D have horizontal phase tilts.

[0072] Next, a method for manufacturing the reception directivity control device 100D according to the second embodiment will be described. FIG. 9 is a flowchart showing the method for manufacturing the reception directivity control device 100D according to the second embodiment. First, the layout of the input lines of the reception directivity control device 100D is determined (step S1). Specifically, the layout of the vertical weighting circuit 50D of the reception directivity control device 100D shown in FIG. 6, the receiving elements 17D-1-1 to 17D-4-4, and the input lines connecting the vertical weighting circuit 50D and the receiving elements 17D-1-1 to 17D-4-4 is determined.

[0073] Next, the total length of the input lines of the reception directivity control device 100D is calculated (step S2). Specifically, the total length of the input lines specified by the layout determined in step S1 is calculated. Next, the layout of the output lines is determined so that the total length of the output lines of the reception directivity control device 100D is the same as the total length of the input lines. Specifically, the layout of the reception elements 17D-1-1 to 17D-4-4, the horizontal weighting circuit 10D, and the output lines is determined so that the total length of the output lines connecting the reception elements 17D-1-1 to 17D-4-4 and the horizontal weighting circuit 10D is the same as the total length of the input lines of the reception directivity control device 100D calculated in step S2.

[0074] Next, a reception directivity control device is manufactured based on the determined layout of the input lines and the determined layout of the output lines (step S4). Specifically, the reception directivity control device 100D is manufactured based on the layout of the vertical weighting circuit 50D, receiving elements 17D-1-1 to 17D-4-4, and input lines determined in step S1, and the layout of the receiving elements 17D-1-1 to 17D-4-4, horizontal weighting circuit 10D, and output lines determined in step S3.

[0075] That is, the manufacturing method of the reception directivity control device 100D includes at least one light source 3D, a vertical weighting circuit 5D (also referred to as a first phase weighting unit) that applies phase weighting in the vertical direction (also referred to as a first direction) to light from the at least one light source 3D, a plurality of reception antennas that receive radio signals (that is, the reception antennas provided in each of the reception elements 17D-1-1 to 17D-1-16), and a plurality of electrical-to-optical conversion units (that is, the electrical-to-optical conversion units provided in each of the reception elements 17D-1-1 to 17D-1-16) that perform electrical-to-optical conversion on the radio signals received by the plurality of reception antennas based on the signals that have been given vertical phase weighting by the vertical weighting circuit 5D. a horizontal weighting circuit 10D (also referred to as a second phase weighting unit) that applies phase weighting in the horizontal direction (also referred to as the second direction) to signals that have been electro-optically converted by the multiple electro-optical conversion units, and a demodulator 16D that demodulates the signals that have been phase-weighted in the horizontal direction by the horizontal weighting circuit 10D, wherein the total length of the input-side lines (lines shown by thick lines in Figure 6) from the multiple electro-optical conversion units is made equal to the total length of the output-side lines (lines shown by dotted lines in Figure 6) from the multiple electro-optical conversion units to the horizontal weighting circuit 10D.

[0076] 9, the case where the layout of the input lines of the reception directivity control device 100D is first determined (step S1 in FIG. 9) and then the layout of the output lines of the reception directivity control device 100D is determined (step S3 in FIG. 9) has been described, but the present invention is not limited to this. For example, the layout of the output lines of the reception directivity control device 100D may be determined first, and then the layout of the input lines of the reception directivity control device 100D may be determined.

[0077] In the second embodiment, a plurality of receiving antennas 1D-1-1 to 1D-116 are equally spaced array antennas arranged in a lattice pattern on the same plane.

[0078] Furthermore, in the second embodiment, the multiple electro-optical converters are provided in a one-to-one correspondence with the multiple receiving antennas, and the multiple electro-optical converters are arranged in a lattice pattern of i rows (i is an integer from 2 to M, however, i=4 in the second embodiment) x j columns (j is an integer from 2 to N, however, j=4 in the second embodiment), and the length of the input line from vertical weighting circuit 5D (also referred to as a first phase weighting unit) to the 1st row x 1st column electro-optical converter (here, the electro-optical converter included in receiving element 17D-1-1) is equal to the length of the output line from the Mth row x Nth column electro-optical converter (here, the electro-optical converter included in receiving element 17D-4-4) to horizontal weighting circuit 10D (also referred to as a second phase weighting unit), and the length of the input line from vertical weighting circuit 5D to the Mth row x Nth column electro-optical converter is equal to the length of the output line from the 1st row x 1st column electro-optical converter to horizontal weighting circuit 10D.

[0079] Furthermore, in the second embodiment, the length of the input line from the vertical weighting circuit 5D (also referred to as the first phase weighting unit) to the 1st row and Nth column electro-optical conversion unit (here, the electro-optical conversion unit included in the receiving element 17D-1-4) is equal to the length of the output line from the Mth row and 1st column electro-optical conversion unit (here, the electro-optical conversion unit included in the receiving element 17D-4-1) to the horizontal weighting circuit 10D (also referred to as the second phase weighting unit), and the length of the input line from the vertical weighting circuit 5D to the Mth row and 1st column electro-optical conversion unit is equal to the length of the output line from the 1st row and Nth column electro-optical conversion unit to the horizontal weighting circuit 10D.

[0080] According to the second embodiment, in addition to the effects obtained in the first embodiment, it is possible to realize a device with a planar circuit configuration suitable for miniaturization, since it is possible to eliminate the need for a delay line and to shorten the lengths of the input and output lines.

[0081] [Third Embodiment] Next, a third embodiment of the present invention will be described. Fig. 10 is a schematic configuration diagram of a reception directivity control device 100E according to the third embodiment of the present invention. The reception directivity control device 100E according to the third embodiment performs an operation of receiving a plurality of RF signals in the same RF frequency band, each of which has a different information signal superimposed thereon (i.e., a multi-beam operation). Note that parts of the configuration of the third embodiment that are similar to those of the first embodiment are assigned the same reference numerals, and their description will be omitted.

[0082] The reception directivity control device 100E according to the third embodiment includes light sources 3E-1 and 3E-2, a vertical weighting circuit 5E (having input terminals 501E and 502E and output terminals 503E and 504E), distributors 7E-1-1 to 7E-2-1, multiplexers 9E-1-1 to 9E-1-2, a horizontal weighting circuit 10E (having input terminals 101E and 102E and output terminals 103E and 104E), receiving elements 17E-1-1 to 17E-2-2, a splitter 18E-1 (having output terminals 181E and 182E), a splitter 18E-2 (having output terminals 183E and 184E), and first to fourth demodulators 19E-1 to 19E-4.

[0083] As shown in Figure 11, when looking from the array antenna into space (into the depths of the paper in Figure 11), the beam in the upper left direction is the first beam B11, the beam in the upper right direction is the second beam B12, the beam in the lower left direction is the third beam B13, and the beam in the lower right direction is the fourth beam B14.

[0084] When CW light from the light source 3E-1 is input to an input terminal 501E of the vertical weighting circuit 5E, the CW light output from the two output terminals 503E and 504E has the same vertical phase tilt as the beams (first beam B11 and second beam B12) in the upward direction in the vertical plane (that is, the CW light output from the two output terminals 503E and 504E has a vertical phase tilt φ Ｖ On the other hand, when CW light from light source 3E-2 is input to input terminal 502E of vertical weighting circuit 5E, the CW light output from two output terminals 503E and 504E has the same vertical phase tilt as the beams (third beam B13 and fourth beam B14) in the downward direction in the vertical plane.

[0085] The first light source 3E-1 outputs CW light in the frequency band of ch1, which is input to an input terminal 501E of the vertical weighting circuit 5E. The second light source 3E-2 outputs CW light in the frequency band of ch2, which is input to an input terminal 502E of the vertical weighting circuit 5E.

[0086] A branching filter 18E-1 is connected downstream of output terminal 103E of horizontal weighting circuit 10E. A branching filter 18E-2 is connected downstream of output terminal 104E of horizontal weighting circuit 10E. Branching filter 18E-1 and distributor 18E-2 have the function of outputting the optical signal of ch1 and the optical signal of ch2 to different terminals, respectively. The configuration of reception directivity control device 100E shown in FIG. 10 makes it possible to simultaneously receive beams in the above four directions and output them to demodulators 19E-1, 19E-2, 19E-3, and 19E-4 connected to different output terminals.

[0087] Next, the operation when receiving the second beam B12 (upper right direction in FIG. 11) will be described. As in the first embodiment, the optical signal from the first light source 3E-1 is output from the output terminal 104E of the horizontal weighting circuit 10E. Since the frequency of this optical signal is ch1, it is output from the output terminal 183E of the demultiplexer 18E-2.

[0088] The optical signal of second light source 3E-2 is modulated by the RF reception signal of second beam B12 by the electro-optical converters provided in each of receiving elements 17E-1-1 to 17E-2-2, and the modulated signals are added together in multiplexers 9E-1-1 and 9E-1-2, respectively. However, because the two optical signals added together in each of multiplexers 9E-1-1 and 9E-1-2 are not in phase, the optical signal of ch2 modulated by the RF reception signal of the second beam is not output from each of multiplexers 9E-1-1 and 9E-1-2 at a sufficient level, and is not input to horizontal weighting circuit 10E. Therefore, the optical signal of second beam B02 is output only from output terminal 183E of demultiplexer 18E-2.

[0089] Next, the operation when receiving fourth beam B14 (to the lower right in FIG. 11) will be described. The optical signal from first light source 3E-1 is modulated by the RF signal of fourth beam B14 by the electro-optical converters provided in each of receiving elements 17E-1-1 to 17E-2-2, and the modulated signals are added together in multiplexers 9E-1-1 and 9E-1-2, respectively. However, because the two optical signals added together in multiplexers 9E-1-1 and 9E-1-2 are not in phase with each other, the optical signal of ch1 modulated by the signal of fourth beam B14 is not output from multiplexers 9E-1-1 and 9E-1-2 at a sufficient level, and is not input to horizontal weighting circuit 10E either.

[0090] The optical signal from second light source 3E-2 has a phase tilt applied by vertical weighting circuit 5E that matches the phase tilt corresponding to the vertical in-plane direction of the beam (downward in FIG. 11 ), so it is added in phase by multiplexers 9E-1-1 and 9E-1-2 and input to horizontal weighting circuit 10E. The horizontal phase tilt of fourth beam B14 is equal to the horizontal phase tilt of second beam B12, so it is output from output terminal 104E of horizontal weighting circuit 10E. Since the frequency of this optical signal is ch2, it is output from output terminal 184E of splitter 18E-2. Thus, the received signal of fourth beam B14 is output only from output terminal 184E of splitter 18E-2.

[0091] The first beam B11 and the third beam B13 are received in the same manner as above, and are output only from output terminals 181E and 182E of branching filter 18E-1, respectively.

[0092] By the above operation, four beams can be received simultaneously, and each received signal can be output from a different terminal for demodulation processing. Note that, although a plurality of optical signals with different frequency bands are used in the third embodiment, the phase calculation shown in Fig. 5 holds true regardless of the frequency band of the optical signal, and therefore the operation shown in the third embodiment holds true for the optical signal of ch1 and the optical signal of ch2.

[0093] In the third embodiment, as shown in FIG. 10 , the total length of the input lines (lines shown by thick lines in FIG. 10 ) from the vertical weighting circuit 5E to the multiple electro-optical converters is equal to the total length of the output lines (lines shown by dotted lines in FIG. 10 ) from the multiple electro-optical converters to the horizontal weighting circuit 10E. This prevents the difference in phase rotation that occurs when the input and output lines are not of equal length from affecting the phase weighting of the array antenna.

[0094] [Fourth Embodiment] Next, a fourth embodiment of the present invention will be described. Fig. 12 is a schematic configuration diagram of a reception directivity control device 100F according to the fourth embodiment of the present invention. Note that parts of the configuration of the fourth embodiment that are similar to those of the first embodiment are given the same reference numerals, and their description will be omitted.

[0095] The reception directivity control device 100F according to the fourth embodiment includes a light source 3F, a vertical weighting circuit 5F (having output terminals 501F, 502F, 503F, and 504F), a vertical scanning instruction circuit 6F, distributors 7F-1-1 to 7F-4-3, multiplexers 9F-1-1 to 9F-3-4, a horizontal weighting circuit 10F (having input terminals 101F, 102F, 103F, and 104F), a horizontal scanning instruction circuit 11F, a beam direction selection circuit 14F, a demodulator 16F, and receiving elements 17F-1-1 to 17F-4-4.

[0096] The fourth embodiment is similar to the first embodiment described above, but does not have row and column delay lines. Here, n=1, 2, 3, and L Ｈ，ｎ are all equal, m=1, 2, 3, L Ｖ，ｍ are all equal, the vertical weighting circuit 5F assigns L to the CW light that leaves each of the receiving elements 17F-1-1 to 17F-4-4 and before entering the horizontal weighting circuit 10F. Ｖ，ｍ The horizontal weighting circuit 10F performs phase weighting by subtracting the vertical phase gradient given by the power supply circuit, and the CW light before it leaves the vertical weighting circuit 5F and enters each element is weighted by the power supply circuit L. Ｈ，ｎ The phase weighting can be performed by subtracting the horizontal phase gradient given by

[0097] In the first to fourth embodiments described above, a matrix circuit is used as a weighting circuit, and the output terminal of the matrix circuit is selected by a switching circuit to select the beam direction. However, the reception directivity control device according to the present invention is not limited to this configuration, and may be configured using a plurality of variable phase shifters, and the beam direction may be set by changing the phase shift amount of the variable phase shifters.

[0098] Furthermore, in the first to fourth embodiments described above, when a radio device capable of both transmission and reception is configured by combining a reception directivity control device and a transmission directivity control device, the reception beam direction of the reception directivity control device may be determined by means of a search or the like, or the reception beam direction of the reception directivity control device may be determined using information on the transmission beam direction used in the transmission directivity control device. In this case, even if the weighting value matrix for the transmission beam and the weighting value matrix for the reception beam are the same due to differences in the installation position and installation direction of the transmitting array antenna and the receiving array antenna, or differences in element arrangement and element characteristics, a weighting circuit correction (calibration) function or a function for associating the transmission beam weighting value matrix and the reception beam weighting value matrix that realizes a reception beam direction corresponding to a certain transmission beam direction (for example, a correspondence table between the index of the transmission beam weighting value matrix and the index of the reception beam weighting value matrix) may be provided.

[0099] In the fourth embodiment, as shown in FIG. 12 , the total length of the input lines (lines shown by thick lines in FIG. 12 ) from the vertical weighting circuit 5F to the multiple electro-optical converters is equal to the total length of the output lines (lines shown by dotted lines in FIG. 12 ) from the multiple electro-optical converters to the horizontal weighting circuit 10F. This prevents the difference in phase rotation that occurs when the input and output lines are not of equal length from affecting the phase weighting of the array antenna.

[0100] The reception directivity control devices 100C to 100F according to the first to fourth embodiments each include a processor such as a CPU (Central Processing Unit) and a memory. The processor executes a program stored in the memory to perform the functions of each unit of the reception directivity control devices 100C to 100F. All or part of the functions of each unit of the reception directivity control devices 100C to 100F may be realized using hardware such as an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array). The above program may be recorded on a computer-readable recording medium. The computer-readable recording medium is, for example, a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, a semiconductor storage device (for example, an SSD (Solid State Drive)), or a storage device such as a hard disk or semiconductor storage device built into a computer system. The above program may be transmitted via a telecommunications line.

[0101] The present invention is applicable to a receiving directivity control device in which it is necessary to prevent a difference in the amount of phase rotation, which occurs when the input line and the output line are not of equal length, from affecting the phase weighting of an array antenna, and to a manufacturing method thereof.

[0102] 1A-1-1 to 1A-2-2, 1B-1-1 to 1B-2-2, 1C-1-2... Receiving antenna, 3A, 3B, 3C, 3D, 3E-1, 3E-2, 3F... Light source, 4A... Vertical trace switching circuit, 5A, 5B, 5C, 5D, 5E, 5F... Vertical direction re-feeding circuit, 6A, 6B, 6C... Vertical trace indication circuit, 7A-1, 7A-2, 7B-1, 7B-2, 7C-1-1 to 7C-3-3, 7D-1-1 to 7D-4-3, 7E-1-1 to 7E-2-1, 7F-1-1 to 7F-4-3... Distributor, 8A-1-1~8A-2-2, 8B-1-1~8B-2-2, 8C-1-2・・・Electro-optical converter, 9A-1, 9A-2, 9B-1, 9B-2, 9C-1-1~9C-3-4, 9D-1-1~ 9D-3-4, 9E-1-1, 9E-1-2, 9F-1-1~9F-3-4・・・Combiner, 10A, 10B, 10C, 10D, 10E, 10F... Horizontal heavy duty circuit, 11A, 11B, 11C... 14A, 14B・・・ビーム direction selection circuit, 15B-1~15B-4, 15C-1~15C-4・・・Extension line, 16B, 16C, 16D・・・Polyphonor, 17C-1-1~17C-1-16, 17D-1-1~17D-4-4, 17E-1-1~17E-2-2, 17F-1- 1~17F-4-4・・・Receiver element 18E-1, 18E-2・・・Demultiplexer 19E-1~19E-4・・・1st~4th polyphonic device

Claims

1. A receiving directivity control device comprising: at least one light source; a first phase weighting unit that imparts a phase weighting in a first direction to light from the at least one light source; a plurality of receiving antennas that receive radio signals; a plurality of electro-optical conversion units that perform electro-optical conversion on the radio signals received by the plurality of receiving antennas based on the signals to which the first phase weighting unit has imparted a phase weighting in the first direction; a second phase weighting unit that imparts a phase weighting in a second direction to the signals to which the plurality of electro-optical conversion units have performed the electro-optical conversion; and a demodulation unit that demodulates the signals to which the second phase weighting unit has imparted a phase weighting in the second direction; 2. The receiving directivity control device according to claim 1, wherein the plurality of receiving antennas are equally spaced array antennas arranged in a lattice pattern on the same plane.

3. The receiving directivity control device according to claim 1, wherein the multiple electro-optical conversion units are provided in a one-to-one correspondence with the multiple receiving antennas, the multiple electro-optical conversion units are arranged in a lattice pattern of i rows (i is an integer from 2 to M) by j columns (j is an integer from 2 to N), the length of the input side line from the first phase weighting unit to the 1st row and 1st column electro-optical conversion unit is equal to the length of the output side line from the Mth row and Nth column electro-optical conversion unit to the second phase weighting unit, and the length of the input side line from the first phase weighting unit to the Mth row and Nth column electro-optical conversion unit is equal to the length of the output side line from the 1st row and 1st column electro-optical conversion unit to the second phase weighting unit.

4. A receiving directivity control device as described in claim 3, wherein the length of the input side line from the first phase weighting unit to the 1st row x Nth column electro-optical conversion unit is equal to the length of the output side line from the Mth row x 1st column electro-optical conversion unit to the second phase weighting unit, and the length of the input side line from the first phase weighting unit to the Mth row x 1st column electro-optical conversion unit is equal to the length of the output side line from the 1st row x Nth column electro-optical conversion unit to the second phase weighting unit.

5. The receiving directivity control device according to claim 1, wherein the at least one light source is a plurality of light sources.

6. A receiving directivity control device according to any one of claims 1 to 3, wherein the first direction is a vertical direction, and the second direction is a horizontal direction.

7. A method for manufacturing a reception directivity control device comprising: at least one light source; a first phase weighting unit that imparts a phase weighting in a first direction to light from the at least one light source; a plurality of receiving antennas that receive radio signals; a plurality of electro-optical conversion units that perform electro-optical conversion on the radio signals received by the plurality of receiving antennas based on the signals to which the first phase weighting unit has imparted a phase weighting in the first direction; a second phase weighting unit that imparts a phase weighting in a second direction to the signals to which the plurality of electro-optical conversion units have performed the electro-optical conversion; and a demodulation unit that demodulates the signals to which the second phase weighting unit has imparted a phase weighting in the second direction, wherein a total length of input side lines from the first phase weighting unit to the plurality of electro-optical conversion units is equal to a total length of output side lines from the plurality of electro-optical conversion units to the second phase weighting unit.

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