Directivity control device and directivity control method

Abstract

An antenna unit has a plurality of antenna elements which are disposed at respective positions where a plurality of parallel first straight lines intersect a plurality of parallel second straight lines orthogonal to the first straight lines in a plane. A first weighting unit converts, into an optical signal, a radio signal which has been received by each of the antenna elements, and gives, to the converted optical signal, a weighting which offsets the difference in phase that occurs in response to the difference in position of the antenna elements in the first straight line direction and a radio signal reception direction. A second weighting unit converts, into an electric signal, the optical signal to which the weighting has been given, and performs, on the converted electric signal, weighting which offsets the difference in phase that occurs in response to the difference in position of the antenna elements in the second straight line direction and a reception direction.

Description

Directivity control device and directivity control method

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

[0002] The use of high-frequency bands, above the millimeter wave band, is progressing as a means of achieving faster and larger-capacity wireless communications. The spatial propagation loss of radio waves increases as the frequency increases. For example, free-space propagation loss increases in proportion to the square of the frequency. Therefore, high-gain antennas are often used in high-frequency bands. High-gain antennas necessarily have high directivity. Therefore, it is necessary to align the beam direction with the other station in wireless communications. In other words, when the direction of the other station is dynamic, a means for dynamically controlling the beam direction, i.e., beam steering, is essential. Furthermore, beam steering in antennas is required not only for wireless communications but also for applications such as radar, imaging, and wireless power transmission.

[0003] As a beam steering method, methods that have been devised and used include mechanically controlling the direction of the antenna, and controlling the radio waves emitted from the antenna by refracting or reflecting them with movable lenses or reflectors. In addition to these, phased array antennas are widely used because they have high durability and movement tracking ability as they do not use mechanical moving parts, and are suitable for making 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 antenna element using means such as variable delay circuits, variable attenuator circuits, and digital signal processing connected to multiple antenna elements arranged on a line or surface.

[0005] Phased array antennas that use analog circuits for weighting are widely used in fifth-generation mobile communication systems and millimeter-wave wireless LAN (Local Area Network) systems that use millimeter-wave bands. Antennas with tens to hundreds of elements are already in practical use.

[0006] As more high-frequency bands are developed, even higher antenna gains are required. Therefore, it is expected that phased array antennas that weight a larger number of antenna elements will be needed. For example, there is a method for configuring a 256-element phased array antenna for use in fifth-generation mobile communication base stations in the 28 GHz band (see, for example, Non-Patent Document 1). For sixth-generation mobile communications, which aim for even higher transmission rates, the use of frequency bands above 100 GHz, the so-called terahertz band, is being considered. For example, if the radio frequency is 10 times higher than the 28 GHz band used in fifth-generation communications, 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 account, it is expected that more than 10,000 antenna elements will be required to compensate for this with the antenna gain of the base station, for example.

[0007] Such multi-element phased array antennas transmit and receive radio waves using highly directional, very narrow beams. The narrow beams allow for simultaneous transmission and reception of multiple beams in the same RF frequency band, each carrying a different information signal (called multi-beam operation). Multi-beam operation enables wireless transmission of more information using a limited RF frequency band, which is expected to dramatically increase the capacity of wireless communication systems.

[0008] To construct a multi-beam control device that controls multiple beams using multiple antenna elements, it is necessary to simultaneously apply phase weighting to multiple antenna elements arranged in two dimensions for multiple radio signals. To achieve this, a three-dimensional matrix-type circuit configuration is required (see, for example, Non-Patent Document 2). This poses problems of difficult planar circuit implementation, manufacturing difficulties, and large size. Manufacturing becomes particularly difficult when there are a large number of antenna elements. Existing technologies that implement weighting using optical circuits include an array antenna device that controls two-dimensional multi-beams using wavelength dispersion lines (see, for example, Patent Document 1). While implementing a three-dimensional matrix-type circuit using optical signal processing could enable miniaturization and planarization, there are no examples of implementation for large-scale antennas, and design and manufacturing challenges are anticipated.

[0009] On the other hand, as mentioned above, phased array antenna modules capable of phase weighting several hundred elements have been put into practical use. Therefore, by combining these with optical technology, it is expected that a directivity control device capable of two-dimensional control of multiple beams using a large-scale phased array antenna with several thousand elements will be easily realized.

[0010] Japanese Patent Application Laid-Open No. 2004-023400

[0011] H. Watanabe, S. Uga, H. Nakamizo, T. Tsutsumi, S. Shinjo, and Y. Kuriyama, "Millimeter-Wave Antenna and RF Front-End Technology for 5th Generation Mobile Communication Base Stations," IEICE Communications Society Magazine, Vol. 14, No. 3, 2020, pp. 222-231. Kim, Dong-Hun et al. "One-Body 2-D Beam-Switching Butler Matrix with Waveguide Short-Slot 2-Plane Couplers." IEICE Transactions on Electronics, 100-C (2017): 884-892.

[0012] As described above, in a multi-beam control device that controls multiple beams using multiple antenna elements, a three-dimensional matrix-type circuit for simultaneously performing phase weighting on antenna elements has the problems of being difficult to manufacture and large in size. Furthermore, implementing a three-dimensional matrix-type circuit using optical signal processing also has the problem of expected difficulties in design and manufacturing.

[0013] In view of the above circumstances, an object of the present invention is to provide a directivity control device and a directivity control method that can realize directivity control of a large-scale array antenna while suppressing an increase in circuit scale.

[0014] One aspect of the present invention is a directivity control device comprising: an antenna unit having a plurality of antenna elements arranged at positions on a plane where a plurality of parallel first lines intersect with a plurality of parallel second lines perpendicular to the first lines; a first weighting unit that converts a radio signal received by each of the antenna elements into a first optical signal and assigns weighting to the converted first optical signal to offset a phase difference that occurs depending on a difference in position of the antenna element in the direction of the first lines and a reception direction of the radio signal; and a second weighting unit that converts the weighted first optical signal into a first electrical signal and assigns weighting to the converted first electrical signal to offset a phase difference that occurs depending on a difference in position of the antenna element in the direction of the second line and a reception direction.

[0015] One aspect of the present invention is a directivity control device comprising: an antenna unit having a plurality of antenna elements arranged at positions on a plane where a plurality of parallel first lines intersect with a plurality of parallel second lines perpendicular to the first lines; a first weighting unit that weights a first electrical signal to be transmitted to impart a phase difference that depends on the difference in position of the antenna elements in the first line direction and the transmission direction of a wireless signal, and converts the weighted first electrical signal into an optical signal; and a second weighting unit that weights the converted optical signal to impart a phase difference that occurs depending on the difference in position of the antenna elements in the second line direction and the transmission direction, converts the weighted optical signal into a second electrical signal, and transmits it wirelessly from the plurality of antenna elements.

[0016] One aspect of the present invention is a directivity control method including: a first weighting step of converting radio signals received by each of the antenna elements of an antenna unit having a plurality of antenna elements arranged at positions on a plane where a plurality of parallel first lines and a plurality of parallel second lines perpendicular to the first lines intersect, into a first optical signal, and assigning weighting to the converted first optical signal to offset a phase difference that occurs depending on a difference in position of the antenna elements in the direction of the first lines and a reception direction of the radio signal; and a second weighting step of converting the weighted first optical signal to a first electrical signal, and assigning weighting to the converted first electrical signal to offset a phase difference that occurs depending on a difference in position of the antenna elements in the direction of the second line and a reception direction.

[0017] One aspect of the present invention is a directivity control method including: a first weighting step of weighting a first electrical signal to be transmitted by weighting the first electrical signal based on a difference in position of the antenna elements in the direction of the first lines and a difference in phase that occurs depending on the transmission direction of a wireless signal in an antenna unit having a plurality of antenna elements arranged at positions where a plurality of parallel first lines intersect with a plurality of parallel second lines perpendicular to the first lines on a plane, and converting the weighted first electrical signal into an optical signal; and a second weighting step of weighting the converted optical signal by weighting the converted optical signal based on a difference in position of the antenna elements in the direction of the second lines and a difference in phase that occurs depending on the transmission direction, converting the weighted optical signal into a second electrical signal, and transmitting the second electrical signal by wireless from the plurality of antenna elements.

[0018] According to the present invention, it is possible to realize a directivity control circuit for a large-scale array antenna while suppressing an increase in circuit size.

[0019] FIG. 1 is a diagram showing an example of the configuration of a directivity control device according to a first embodiment of the present invention. FIG. 2 is a diagram showing an example of the configuration of an optical weighting circuit according to the first embodiment. FIG. 3 is a diagram showing an example of the configuration of a directivity control device according to a third embodiment. FIG. 4 is a diagram showing an example of the configuration of a portion from an antenna element to an electro-optical / photoelectric conversion unit according to the third embodiment. FIG. 5 is a diagram showing an example of the configuration of a portion from an antenna element to an electro-optical / photoelectric conversion unit according to the third embodiment. FIG. 6 is a diagram showing an example of the configuration of a directivity control device according to a fourth embodiment. FIG. 7 is a diagram showing an example of the configuration of a directivity control device according to a fifth embodiment.

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are merely examples, and the embodiments to which the present invention is applicable are not limited to the following embodiments.

[0021] An embodiment of the present invention relates to a method for configuring a large-scale phased array antenna capable of multiple beams, which is necessary for controlling the directivity of a large number of radio wave beams with sharp directivity in ultra-high speed and large capacity wireless transmission using radio waves in high frequency bands such as millimeter wave bands and terahertz bands, high definition imaging, radar, etc. This embodiment makes it possible to realize a large-scale array antenna, which has been difficult to realize using only existing electronic circuit-type directivity control circuits, while utilizing existing electronic circuit-type directivity control circuits.

[0022] [First Embodiment] The first embodiment shows the basic configuration of a directivity control device used in a receiver.

[0023] FIG. 1 is a diagram showing an example of the configuration of a directivity control device 1 according to a first embodiment of the present invention. The directivity control device 1 is a receiving directivity control device. The directivity control device 1 includes J×I antenna elements 11, J×I electro-optical (EO) converters 12, J multiplexers 13, optical weighting circuits 14, K demultiplexers 15, K×I optical-electrical (OE) converters 16, and K beam control modules 17 (I, J, and K are each an integer of 2 or greater). The following description will be given using an example where I=16, J=100, and K=10. K is the number of beams. The kth (k is an integer greater than or equal to 1 and less than or equal to K) receiving beam in the receiving direction will be referred to as receiving beam Bk.

[0024] The directivity control device 1 is configured with a two-dimensional array antenna 10 in which I antenna elements 11 (16 in FIG. 1 ) are arranged in the vertical direction (vertical direction) and J antenna elements 11 (100 in FIG. 1 ) are arranged in a grid. That is, I is the number of antenna elements arranged in a vertical line, and J is the number of antenna elements arranged in a horizontal line. The 16 antenna elements 11 in one vertical column constituting the jth column (j is an integer between 1 and 100) of the two-dimensional array antenna 10 are referred to as antenna elements 11-j-1 to 11-j-16. That is, the antenna elements 11-j-1 to 11-j-16 in the jth column are antenna elements 11 located on the same vertical line and at the same position in the horizontal direction. The 100 antenna elements 11-1-i to 11-100-i in one horizontal row that make up the ith row (i is an integer between 1 and 16) of the two-dimensional array antenna 10 are located on the same horizontal line and are antenna elements 11 that are located at the same vertical position. As described above, the antenna elements 11 are arranged at each position where multiple parallel vertical lines (columns) intersect with parallel horizontal lines (rows). The two-dimensional array antenna 10 receives reception beams B1 to B10.

[0025] The electro-optical converter 12 provided downstream of each antenna element 11-ji is referred to as an electro-optical converter 12-ji. The electro-optical converter 12-ji converts the RF (Radio Frequency) signal received by the antenna element 11-ji into an optical signal. The electro-optical converter 12 is composed of, for example, an optical modulator. CW (Continuous Wave) light supplied from a light source (not shown) is input to the optical modulator. The optical modulator of the electro-optical converter 12-ji modulates the CW light from the light source with the RF signal from the antenna element 11-ji, thereby converting the RF signal into an optical signal. The modulation method used here may be intensity modulation (a signal whose envelope amplitude is proportional to the RF signal waveform), double sideband modulation, single sideband modulation, or phase modulation.

[0026] A different optical frequency band is assigned to each of the optical signals output from the electrical-to-optical converters 12-j-1 to 12-j-16 belonging to the same column. For example, the frequency band of the optical signal output from the electrical-to-optical converter 12-j-i is the optical frequency channel chi (i is an integer between 1 and 16). Therefore, RF signals output from the antenna elements 11-1-i to 11-100-i at the same horizontal position are converted into optical signals of the same optical frequency channel chi. The frequency intervals of the optical frequency channels may be equal or unequal. Hereinafter, the optical frequency channel will also be simply referred to as a channel.

[0027] The J multiplexers 13 are referred to as multiplexers 13-1 to 13-J. The outputs from the electrical-to-optical converters 12-j-1 to 12-j-16 connected to the antenna elements 11-j-1 to 11-j-16 in the jth column are input to one multiplexer 13-j. The multiplexer 13-j generates an optical multiplexed signal, which is a multiplexed signal obtained by optically wavelength-multiplexing (optical frequency-multiplexing) the optical signals of different channels ch1 to ch16 input from the electrical-to-optical converters 12-j-1 to 12-j-16. The multiplexer 13-j inputs the generated optical multiplexed signal to the jth input terminal 142-j of the 100 input terminals 142 of the optical weighting circuit 14.

[0028] The direction of the received beam B1 is set to the right in the horizontal plane when viewing space from the two-dimensional array antenna 10. In this case, there is a phase difference (phase tilt) between the RF signals received by adjacent antenna elements 11 in the horizontal plane. Hereinafter, this phase tilt will be referred to as horizontal phase tilt. Specifically, for example, the RF signal received by antenna element 11-2-1 has a predetermined phase difference (phase tilt) φ from the RF signal received by antenna element 11-1-1. Ｈ This phase difference is due to the difference in arrival time of radio waves arriving at each antenna element 11 from the right. If the antenna elements 11 are arranged at equal intervals in the horizontal direction, as in the above, the RF signal received by antenna element 11-2-2 will be delayed by φ from the RF signal received by antenna element 11-1-2. Ｈ It's just delayed.

[0029] The optical weighting circuit 14 forms a multi-terminal matrix circuit for optical applications. The optical weighting circuit 14 has 100 input terminals 142 and 10 output terminals 147. The 100 input terminals 142 are respectively referred to as input terminals 142-1 to 142-100, and the 10 output terminals 147 are respectively referred to as output terminals 147-1 to 147-10. The input terminal 142-j receives an optical frequency-multiplexed optical multiplexed signal from the multiplexer 13-j.

[0030] When the electro-optical converter 12 is an intensity modulator, the upper sideband (USB) component of the optical signal of each reception beam Bk that is optically frequency multiplexed into the 100-stream optical multiplexed signal input to the input terminals 142-1 to 142-100 of the optical weighting circuit 14 has the same horizontal phase tilt as the RF signal. Specifically, for example, in each optical frequency channel chi (i is an integer between 1 and 16), the USB component of the optical signal of the reception beam Bk in the multiplexed signal input to the input terminal 142-j' (j' is an integer between 2 and 100) has a phase difference of φ depending on the reception direction of the reception beam Bk, compared to the USB component of the optical signal of the reception beam Bk in the optical multiplexed signal input to the input terminal 142-(j'-1). Ｈ It's just delayed.

[0031] On the other hand, when the lower sideband (LSB) component of the optical signal of each reception beam Bk that is optically frequency multiplexed into the 100-stream optical multiplexed signal input to input terminals 142-1 to 142-100 of the optical weighting circuit 14 is examined, it is found to have a horizontal phase tilt with an opposite sign to that of the RF signal. Specifically, for example, in each optical frequency channel chi (i is an integer between 1 and 16), the USB component of the optical signal of reception beam Bk in the optical multiplexed signal input to input terminal 142-j' (j' is an integer between 2 and 100) has a phase difference φ depending on the reception direction of reception beam Bk, compared to the USB component of the optical signal of reception beam Bk in the optical multiplexed signal input to input terminal 142-(j'-1). Ｈ It's just progressing.

[0032] The optical weighting circuit 14 is a 100 x 10 matrix circuit that applies a predetermined optical phase weighting to each of the optical multiplexed signals input from 100 input terminals 142 and outputs the signals to 10 output terminals 147 corresponding to the receiving beams B1 to B10. The optical phase weighting cancels out the phase difference between the input optical signals that arises due to the difference in the horizontal position of the antenna elements 11-1-i to 11-100-i at which each wireless signal is received and the receiving direction of the receiving beam Bk. Here, the predetermined optical phase weighting value is set according to the in-plane direction information of the receiving beam Bk to be received. The in-plane direction information may be automatically determined by a beam direction detection (so-called beam search) means and input to the optical weighting circuit 14, or it may be input by the user. For example, if the received beam Bk is the desired signal, the optical weighting circuit 14 applies an optical phase weighting to each of the multiplexed signals input from the 100 input terminals 142 to offset the horizontal phase tilt according to the received beam Bk, and combines the optical phase-weighted multiplexed signals to output them from the output terminal 147 according to the received beam Bk.

[0033] The optical weighting circuit 14 may be configured, for example, to split signals input from each of the input terminals 142-1 to 142-100 into 10, and output the split signals from each of the output terminals 147-1 to 147-10 via variable phase shifters and variable attenuators that adjust the phase and amplitude of each split signal. In this configuration, before each output terminal 147, the 100 streams of optical signals input from the input terminals 142-1 to 142-100 and having their amplitudes and phases adjusted are multiplexed into one. For example, the optical weighting circuit 14 may have the configuration shown in FIG. 2.

[0034] 2 is a diagram showing an example configuration of the optical weighting circuit 14. The optical weighting circuit 14 is configured, for example, by combining an optical matrix circuit 141 and an optical switching circuit 145. The optical matrix circuit 141 has input terminals 142-1 to 142-100 and output terminals 143-1 to 143-100. The optical matrix circuit 141 is, for example, a multiple-input, multiple-output fixed weighting matrix optical circuit such as a Butler matrix or a Brass matrix. The optical switching circuit 145 has input terminals 146-1 to 146-100 and output terminals 147-1 to 147-100. The input terminal 146-j inputs an optical signal from the output terminal 143-j of the optical matrix circuit 141. In the case of the received beam Bk, the optical switching circuit 145 weights the optical signals input from the input terminals 146-1 to 146-100 in accordance with the horizontal plane scanning direction information, combines them, and outputs them from the output terminal 147-k.

[0035] When receiving a reception beam Bk, the optical weighting circuit 14 weights the USB components of the 100 optical signals input from input terminals 142-1 to 142-100 with a weighting factor of -1 times the phase tilt of the reception beam Bk, and outputs the weighted signal from output terminal 147-k. At this time, the optical phases of the USB components of the 100 optical signals are all aligned at output terminal 147-k, and they are combined in phase. This operation is true for all optical frequency channels ch1 to ch16. Hereinafter, only the USB components of the optical signals will be described.

[0036] When receiving the reception beam Bk, the optical weighting circuit 14 may weight the LSB components of the 100 optical signals input from the input terminals 142-1 to 142-100 by +1 times the phase tilt, and output them from the output terminal 147-k. At this time, the LSB components of the 100 optical signals are combined in phase at the output terminal 147-k. Weighting may be performed in this manner using the LSB.

[0037] The demultiplexer 15 downstream of the optical weighting circuit 14 shown in FIG. 1 has the same number of output ports as the number I of antenna elements in the vertical direction. The demultiplexer 15 corresponding to the received beam Bk is referred to as demultiplexer 15-k. The demultiplexer 15-k demultiplexes the optical signal output from output terminal 147-k of the optical weighting circuit 14 into optical signals of channels ch1 to ch16, and outputs the demultiplexed optical signals to each of the 16 downstream photoelectric conversion units 16. The photoelectric conversion unit 16 corresponding to channel chi of the received beam Bk is referred to as photoelectric conversion unit 16-k-i. The photoelectric conversion unit 16 converts the input optical signal into an electrical signal.

[0038] As described above, the optical signal of the reception beam Bk output from the output terminal 147-k of the optical weighting circuit 14 has components of optical frequency channels ch1 to ch16. Therefore, the components of the optical frequency channels ch1 to ch16 are separated in the demultiplexer 15-k and converted into electrical signals in the photoelectric conversion units 16-k-1 to 16-k-16, respectively. The photoelectric conversion unit 16 is a component that has the function of inputting, for example, the USB component of the input optical signal and an optical carrier signal that is separated from the USB component by the frequency of the RF signal (or IF (intermediate frequency)) into a photodiode and converting them into electrical signals (RF signals or IF signals).

[0039] The beam control module 17 is an electronic circuit-type beam control module. The beam control module 17 corresponding to the received beam Bk is referred to as beam control module 17-k. An existing electronic circuit-type beam control module can be used for the beam control module 17. The electrical signals output from the photoelectric conversion units 16-k-1 to 16-k-16 have a phase gradient that depends on the vertical in-plane direction of the received beam Bk. Therefore, these signals are electrically weighted in the beam control module 17-k to perform reception and demodulation processing. This weighting offsets the phase difference that occurs depending on the difference in the vertical position of the antenna element 11 where each electrical signal is received and the direction of arrival of the received beam Bk. This weighting is performed based on the vertical in-plane direction information of the received beam Bk. The electronic circuit-type beam control module used as the beam control module 17 is a module that performs phase weighting processing for an electrical circuit-type phased array antenna manufactured for use in, for example, fifth-generation mobile communication radio equipment, and may also have a demodulation processing function.

[0040] The directivity control device 1 according to this embodiment can receive multiple beams. For example, while receiving a received beam Bk, it can also receive a received beam Bk' (where k ≠ k' and k' = 1 to 10) that arrives from a different direction from the received beam Bk and has a different information signal superimposed thereon in the same RF frequency band as the received beam Bk. When receiving the received beam Bk', the optical weighting circuit 14 weights the USB components of 100 optical signals input from input terminals 142-1 to 142-100 by a factor of -1, which is the phase tilt of the received beam Bk', and outputs the weighted signals from output terminal 147-k'. The beam control module 17-k' electrically weights the received beam Bk' based on the vertical in-plane direction information and performs reception and demodulation processing. The configuration shown in this embodiment can receive multiple beams of up to 10 beams.

[0041] The directivity control device 1 detects the received beam Bk １ and receiving beam Bk ２ When receiving a radio signal of k, the following operation is performed: １ ≠k２、 And k １ and k ２ is an integer between 1 and K. The two-dimensional array antenna 10 of the directivity control device 1 receives a beam Bk １ and receiving beam Bk ２ The two-dimensional array antenna 10 receives a radio signal. Each antenna element 11-1-1 to 11-100-16 outputs the received RF signal. The electrical-to-optical converters 12-j-1 to 12-j-16, where j = 1 to 100, convert the RF signals received by the antenna elements 11-j-1 to 11-j-16 into optical signals of channels ch1 to ch16, respectively, and output the converted optical signals to the multiplexer 13-j. The multiplexers 13-1 to 13-100 optically wavelength-multiplex the input optical signals to generate optical multiplexed signals, and output the generated optical multiplexed signals to the input terminals 142-1 to 142-100 of the optical weighting circuit 14.

[0042] The optical weighting circuit 14 weights the 100 optical multiplexed signals input from the input terminals 142-1 to 142-100 with the received beam Bk １ Based on the horizontal plane direction information, the difference in the horizontal position of the antenna element 11 and the reception beam Bk １ and outputs the optical phase-weighted optical multiplexed signal to output terminal 147-k. １ The optical weighting circuit 14 also weights the 100 optical multiplexed signals input from the input terminals 142-1 to 142-100 with the received beam Bk ２ Based on the horizontal plane direction information, the difference in the horizontal position of the antenna element 11 and the reception beam Bk ２ and outputs the optical phase-weighted optical multiplexed signal to output terminal 147-k. ２ Output from

[0043] Duplexer 15-k １ is the output terminal 147-k １ The optical multiplexed signal received from the optical converter 16-k is separated into optical signals of channels ch1 to ch16. １ -1 to 16-k １The signal is output to each of the photoelectric conversion units 16-k where i=1 to 16. １ -i converts the optical signal of channel ch1i into an electrical signal, and the beam control module 17-k １ The beam control module 17-k outputs the signal to the beam control module 17-k. １ is the photoelectric conversion unit 16-k １ -1 to 16-k １ -16, the received beam Bk １ Based on the vertical plane direction information, the difference in the vertical position of the antenna element 11 and the received beam Bk １ The phase gradient in the vertical direction occurring in accordance with the receiving direction is weighted by −1.

[0044] On the other hand, the duplexer 15-k ２ is the output terminal 147-k ２ The optical multiplexed signal received from the optical converter 16-k is separated into optical signals of channels ch1 to ch16. ２ -1 to 16-k ２ The signal is output to each of the photoelectric conversion units 16-k where i=1 to 16. ２ -1 to 16-k ２ -16 converts the optical signal of channel chi into an electrical signal, and the beam control module 17-k ２ The beam control module 17-k outputs the signal to the beam control module 17-k. ２ is the photoelectric conversion unit 16-k ２ -1 to 16-k ２ -16, the received beam Bk ２ Based on the vertical plane direction information, the difference in the vertical position of the antenna element 11 and the received beam Bk ２ The phase gradient in the vertical direction occurring in accordance with the receiving direction is weighted by −1.

[0045] Regarding the two-dimensional directions shown in this embodiment, the horizontal and vertical directions may be reversed, or the directions may be east-west and north-south.

[0046] According to this embodiment, by installing the same number of existing electronic circuit type beam control modules compatible with several tens of elements as the number of multiplexed beams, it becomes possible to multiplex control several thousand elements and several tens of beams.

[0047] Second Embodiment The second embodiment shows the basic configuration of a directivity control device used in a transmitter.

[0048] FIG. 3 is a diagram showing the configuration of a directivity control device 3 according to a second embodiment of the present invention. The directivity control device 3 is a transmission directivity control device. The directivity control device 3 includes K beam control modules 31, K×I electro-optical (EO) converters 32, K multiplexers 33, optical weighting circuits 34, J demultiplexers 35, J×I optical-electrical (OE) converters 36, and J×I antenna elements 37 (I, J, and K are each an integer of 2 or greater). The following description uses an example where I=16, J=100, and K=10. K is the number of beams. The kth (k is an integer greater than or equal to 1 and less than or equal to K) transmission beam in the transmission direction is referred to as transmission beam Ck.

[0049] Similar to the two-dimensional array antenna 10 of the directivity control device 1 of the first embodiment, the two-dimensional array antenna 30 of the directivity control device 3 is configured by arranging 16 antenna elements 37 in the vertical direction and 100 antenna elements 37 in the horizontal direction on a grid. The 16 antenna elements 37 in one vertical column constituting the j-th column (j is an integer between 1 and 100) of the two-dimensional array antenna 30 are referred to as antenna elements 37-j-1 to 37-j-16. Transmission beams C1 to C10 are transmitted from the two-dimensional array antenna 30.

[0050] The beam control module 31 is an electronic circuit type beam control module. An electronic circuit type beam control module based on existing technology can be used as the beam control module 31. The 10 beam control modules 31 are referred to as beam control modules 31-1 to 31-10. The 16 electro-optical conversion units 32 connected to the beam control module 31-k are referred to as electro-optical conversion units 32-k-1 to 32-k-16. The multiplexer 33 connected to the electro-optical conversion units 32-k-1 to 32-k-16 is referred to as multiplexer 33-k.

[0051] When transmitting a transmission beam Ck, beam control module 31-k outputs 16 RF signals (or IF signals) electrically weighted corresponding to the vertical phase tilt to electrical-optical converters 32-k-1 to 32-k-16. Weighting the RF signals corresponding to the vertical phase tilt imparts a phase difference to the RF signals that occurs depending on the difference in the vertical position of antenna element 37 from which each RF signal is transmitted and the transmission direction of transmission beam Ck. Beam control module 31-k obtains the vertical phase tilt of transmission beam Ck from the vertical in-plane direction information of the input beam direction information. Electrical-optical converters 32-k-1 to 32-k-16 each convert the RF signals input from beam control module 31-k into optical signals and output them to multiplexer 33-k.

[0052] A different optical frequency band is assigned to each of the optical signals output from the electro-optical conversion units 32-k-1 to 32-k-16 in the column direction. The multiplexer 33-k multiplexes the optical signals input from each of the electro-optical conversion units 32-k-1 to 32-k-16, optically wavelength-multiplexing the multiplexed signal, and inputs the multiplexed signal to the input terminal 342-k, which is the kth input terminal 342 of the ten input terminals 342 of the optical weighting circuit 34. For example, the frequency band of the optical signal output from the electro-optical conversion unit 32-k-i is channel chi (i is an integer between 1 and 16). In other words, the electrical signals radiated by radio waves from the antenna elements 37-1-i to 37-100-i located at the same horizontal position are converted into optical signals of the same optical frequency channel chi. The frequency intervals of the channels may be equal or unequal.

[0053] The electro-optical converter 32 has a function of converting an RF signal (or an IF signal) into an optical signal. The electro-optical converter 32 is configured, for example, by an optical modulator. CW light supplied from a light source (not shown) is input to the optical modulator. The optical modulator modulates the input CW light with the RF signal output from the beam control module 31, thereby converting the RF signal into an optical signal. The modulation method used here may be intensity modulation (a signal having a waveform whose envelope amplitude is proportional to the RF signal waveform), double sideband modulation, single sideband modulation, or phase modulation.

[0054] The outputs from the electrical-to-optical converters 32-k-1 to 32-k-16 are input to one multiplexer 32-k. The multiplexer 32-k optically wavelength-multiplexes (optical frequency-multiplexes) the optical signals of different channels ch1 to ch16 input from the electrical-to-optical converters 32-k-1 to 32-k-16 to generate an optical multiplexed signal, which is a multiplexed signal. The multiplexer 32-k inputs the generated optical multiplexed signal to the k-th input terminal 342-k of the ten input terminals 342 of the optical weighting circuit 34.

[0055] The optical weighting circuit 34 has 10 input terminals 342 and 100 output terminals 347. The 10 input terminals 342 are respectively referred to as input terminals 342-1 to 342-10, and the 100 output terminals 347 are respectively referred to as output terminals 347-1 to 347-100. The input terminal 342-k inputs the optical multiplexed signal output from the multiplexer 33-k.

[0056] The optical weighting circuit 34 divides the optical multiplexed signal input from the input terminal 342-k into 100 signals, assigns weighting to the divided optical multiplexed signals equal to the horizontal phase tilt required to form a transmission beam Ck in the horizontal plane for the USB component, and outputs each optical signal from the output terminals 347-1 to 347-100. The weighting value equal to the horizontal phase tilt of the transmission beam Ck is obtained based on the vertical plane direction information of the transmission beam Ck to be transmitted. By assigning a weighting equivalent to the horizontal phase tilt, a phase difference is imparted to the optical signal that occurs depending on the difference in the horizontal position of the antenna element 37 from which each RF signal converted from the optical signal is transmitted and the transmission direction of the transmission beam Ck. This operation is performed for all optical frequency channels ch1 to ch16 of each transmission beam Ck. Hereinafter, only the USB component of the optical signal will be described.

[0057] When transmitting the transmission beam Ck, the optical weighting circuit 34 may weight the LSB component of the optical signal input from the input terminal 342-k and branched into 100 signals by −1 times the horizontal phase tilt of the transmission beam Ck, and output each optical signal from the output terminals 347-1 to 347-100. This operation is performed for all optical frequency channels ch1 to ch16 of each transmission beam Ck. Weighting may be performed in this manner using the LSB.

[0058] The 100 duplexers 35 are referred to as duplexers 35-1 to 35-100. Each duplexer 35-j corresponds to antenna elements 37-j-1 to 37-j-16 arranged in a vertical line. The duplexer 35-j is connected to an output terminal 347-j (j is an integer between 1 and 100) of the optical weighting circuit 34. The 16 photoelectric conversion units 36 connected to the duplexer 35-j are referred to as photoelectric conversion units 36-j-i. The photoelectric conversion units 36-j-i are connected to the antenna elements 37-j-i.

[0059] The optical signal of the transmission beam Ck output from each of the output terminals 347-1 to 347-100 of the optical weighting circuit 34 has components of optical frequency channels ch1 to ch16. The optical signal is then separated into its respective optical frequency channel components in each of the demultiplexers 35-1 to 35-100. Each optical frequency channel component is converted into an electrical signal in each of the photoelectric converters 36. That is, the channel component of channel chi transmitted from the jth antenna element 37 is converted into an electrical signal in the photoelectric converter 36-ji. The electrical signal converted by the photoelectric converter 36-ji is radiated into space from the connected antenna element 37-ji. The photoelectric converter 36 is a component that, for example, inputs the USB component of the input optical signal and an optical carrier signal that is separated from the USB component by the frequency of the RF signal into a photodiode and converts them into an RF electrical signal.

[0060] In the two-dimensional array antenna 30, 16 RF signals radiated from antenna elements 37-j-1 to 37-j-16 (j is an integer between 1 and 100) arranged in the column direction have a vertical phase tilt provided by the beam control module 31-k, and contribute to forming a vertical beam of the transmission beam Ck. On the other hand, RF signals radiated from antenna elements 37-1-i to 37-100-i (i is an integer between 1 and 16) arranged in the row direction have a horizontal phase tilt provided by the optical weighting circuit 34, and contribute to forming a horizontal beam of the transmission beam Ck.

[0061] The directivity control device 3 according to this embodiment can transmit multiple beams. For example, while transmitting a transmission beam Ck, it can also transmit a transmission beam Ck' (where k ≠ k' and k' = 1 to 10) in a direction different from that of the transmission beam Ck, in the same RF frequency band as the transmission beam Ck but with a different information signal superimposed thereon. When transmitting the transmission beam Ck', the optical weighting circuit 34 assigns a weighting equal to the phase tilt of the transmission beam Ck' to the USB component of the optical signal input from the input terminal 342-k', and outputs the weighted signal from the output terminals 347-1 to 347-100. The photoelectric conversion units 36-j-1 to 36-j-16, where j = 1 to 100, convert the optical signal output from the output terminal 347-j of the optical weighting circuit 34 into RF signals for each optical frequency channel, and radiate the RF signals into space from the antenna elements 37-j-1 to 37-j-16. The configuration shown in this embodiment can perform multi-beam transmission with a maximum of 10 beams.

[0062] The directivity control device 3 transmits the beam Ck １ and the transmitted beam Ck ２ When transmitting a radio signal of k, the operation is as follows: １ ≠k ２、 And k １ and k ２ is an integer between 1 and K.) Beam control module 31-k １ splits the RF signal into 16 beams, １ The beam control module 31-k electrically weights the beams corresponding to the vertical phase gradient of the beams. １ are weighted RF signals to the electric-to-optical converters 32-k. １ -1 to 32-k １ -16. １ -1 to 32-k １ -16 convert the RF signals into optical signals of channels ch1 to ch16, and multiplexers 33-k １ The signal is output to the multiplexer 33-k. １ is the electrical-optical conversion unit 32-k １ -1 to 32-k １The optical signals input from each of the optical weighting circuits 34 are multiplexed and optically wavelength-multiplexed, and output to the input terminal 342-k of the optical weighting circuit 34. １ Enter.

[0063] Similarly, the beam control module 31-k ２ splits the RF signal into 16 beams, ２ The beam control module 31-k electrically weights the beams corresponding to the vertical phase gradient of the beams. ２ are weighted RF signals to the electric-to-optical converters 32-k. ２ -1 to 32-k ２ -16. ２ -1 to 32-k ２ -16 convert the RF signals into optical signals of channels ch1 to ch16, and multiplexers 33-k ２ The signal is output to the multiplexer 33-k. ２ is the electrical-optical conversion unit 32-k ２ -1 to 32-k ２ The optical signals input from each of the optical weighting circuits 34 are multiplexed and optically wavelength-multiplexed, and output to the input terminal 342-k of the optical weighting circuit 34. ２ Enter.

[0064] The optical weighting circuit 34 has an input terminal 342-k １ The optical signal input from is divided into 100, and the transmitted beam Ck is generated in the horizontal plane for the USB component of the divided optical signal. １ The optical weighting circuit 34 applies a weight equal to the horizontal phase tilt required to form the optical signals, and outputs the optical signals from the output terminals 347-1 to 347-100. ２ The optical signal input from is divided into 100, and the transmitted beam Ck is generated in the horizontal plane for the USB component of the divided optical signal. ２ Each optical signal is output from output terminals 347-1 to 347-100. １ and the transmitted beam Ck ２ The optical signal is multiplexed with the optical signal of the first optical signal and output.

[0065] The demultiplexers 35-1 to 35-100 separate the optical signals output from the output terminals 347-1 to 347-100 of the optical weighting circuit 34 into optical signals of channels ch1 to ch16. Each demultiplexer 35-j, where j = 1 to 100, outputs the separated optical signal of channel chi to photoelectric conversion units 36-j-1 to 36-j-16. The photoelectric conversion units 36-1-1 to 36-100-16 convert the input optical signals into RF signals and radiate them into space from the antenna elements 37-1-1 to 37-100-16.

[0066] Regarding the two-dimensional directions shown in this embodiment, the horizontal and vertical directions may be reversed, or the directions may be east-west and north-south.

[0067] Third Embodiment In a third embodiment, the configuration of a directivity control device for both transmission and reception will be described.

[0068] 4 is a diagram showing an example of the configuration of a directivity control device 5 according to this embodiment. The directivity control device 5 is configured to function as both a transmitter and a receiver. The directivity control device 5 includes J×I antenna elements 11, J×I electro-optical / optical-electrical converters (EO / OE) 52, J multiplexers / demultiplexers 53, optical weighting circuits 54, K multiplexers / demultiplexers 55, K×I electro-optical / optical-electrical converters (EO / OE) 56, and K beam control modules 57 (I, J, and K are each an integer greater than or equal to 2). The following description will be given using an example where I=16, J=100, and K=10, where K is the number of beams.

[0069] The two-dimensional array antenna 10 of the directivity control device 5 is configured in the same manner as the two-dimensional array antenna 10 of the directivity control device 1 of the first embodiment, by arranging 16 antenna elements 11 in the vertical direction and 100 antenna elements 11 in the horizontal direction on a grid.

[0070] The electro-optical / photoelectric conversion unit 52 connected to the antenna element 11-ji-i will be referred to as electro-optical / photoelectric conversion unit 52-ji, and the multiplexer / demultiplexer 53 connected to the electro-optical / photoelectric conversion units 52-j-1 to 52-j-16 will be referred to as the multiplexer / demultiplexer 53-j (where i is an integer between 1 and I, and j is an integer between 1 and J). The K multiplexers / demultiplexers 55 will be referred to as the multiplexers / demultiplexers 55-1 to 55-K, the 16 electro-optical / photoelectric conversion units 56 connected to the multiplexer / demultiplexer 55-k will be referred to as the electro-optical / photoelectric conversion units 56-k-1 to 56-k-16, and the beam control module 57 connected to the electro-optical / photoelectric conversion units 56-k-1 to 56-k-16 will be referred to as the beam control module 57-k (where k is an integer between 1 and K). The optical weighting circuit 54 has J first terminals 542 and K second terminals 547. The first terminal 542 connected to the multiplexer / demultiplexer 53-j is referred to as a first terminal 542-j, and the second terminal 547 connected to the multiplexer / demultiplexer 55-k is referred to as a second terminal 547-k.

[0071] The beam control module 57 is an electronic circuit type beam control module. An electronic circuit type beam control module based on existing technology can be used as the beam control module 57. Many electronic circuit type beam control modules are commercially available as devices for both transmission and reception, assuming TDD (time division duplex) operation. Furthermore, most of the optical circuits are passive circuits and have reversibility. Therefore, in this embodiment, the electro-optical / photoelectric conversion unit 52 and the electro-optical / photoelectric conversion unit 56 are configured to selectively operate as either an opto-electric conversion unit or an electro-optic conversion unit during transmission and reception.

[0072] That is, when receiving a wireless signal, the electro-optical / photoelectric conversion units 52-1-1 to 52-100-16, multiplexer / demultiplexers 53-1 to 53-100, optical weighting circuit 54, multiplexer / demultiplexers 55-1 to 55-10, electro-optical / photoelectric conversion units 56-1-1 to 56-10-16, and beam control modules 57-1 to 57-10 of the directivity control device 5 operate in the same manner as the electro-optical conversion units 12-1-1 to 12-100-16, multiplexers 13-1 to 13-100, optical weighting circuit 14, demultiplexers 15-1 to 15-10, photoelectric conversion units 16-1-1 to 16-10-16, and beam control modules 17-1 to 17-10 of the first embodiment, respectively. In this case, the first terminals 542-1 to 542-100 of the light weighting circuit 54 correspond to the input terminals 142-1 to 142-100 of the light weighting circuit 14, and the second terminals 547-1 to 547-10 of the light weighting circuit 54 correspond to the output terminals 147-1 to 147-10 of the light weighting circuit 14.

[0073] Furthermore, when transmitting a radio signal, the beam control modules 57-1 to 57-10 of the directivity control device 5, the electric-optical / optical-electrical conversion units 56-1-1 to 56-10-16, the multiplexer / demultiplexers 55-1 to 55-10, the optical weighting circuit 54, the multiplexer / demultiplexers 53-1 to 53-100, the electric-optical / optical-electrical conversion units 52-1-1 to 52-100-16, and the antenna elements 11-1-1 to 11-100-1 6 operate in the same manner as the beam control modules 31-1 to 31-10, electrical-to-optical converters 32-1-1 to 32-10-16, multiplexers 33-1 to 33-10, optical weighting circuit 34, demultiplexers 35-1 to 35-100, optical-to-electrical converters 36-1-1 to 36-100-16, and antenna elements 37-1-1 to 37-100-16 in the second embodiment. In this case, second terminals 547-1 to 547-10 of optical weighting circuit 54 correspond to input terminals 342-1 to 342-10 of optical weighting circuit 34, and first terminals 542-1 to 542-100 of optical weighting circuit 54 correspond to output terminals 347-1 to 347-100 of optical weighting circuit 34. Directivity control device 5 switches between receiving and transmitting operations over time.

[0074] 5 shows the configuration of the portion indicated by the symbol A in FIG. 4 from the antenna element 11-1-1 to the electrical-optical / optical-electrical conversion unit 52-1-1. The antenna element 11-1-1 is connected to the electrical-optical conversion unit 12-1-1 and the optical-electrical conversion unit 36-1-1 via an RF circulator 551. With respect to RF signals, the electrical-optical conversion unit 12-1-1 and the optical-electrical conversion unit 36-1-1 are isolated from each other. Furthermore, the electrical-optical conversion unit 12-1-1 and the optical-electrical conversion unit 36-1-1 are connected to terminals of the multiplexer / demultiplexer 53-1 via an optical circulator 554. The electrical-optical conversion unit 12-1-1 and the optical-electrical conversion unit 36-1-1 are isolated from each other with respect to optical signals.

[0075] When receiving a wireless signal, the electrical-to-optical converter 12-1-1 inputs the RF signal obtained by the antenna element 11-1-1, converts it into an optical signal, and outputs it to the multiplexer / demultiplexer 53-1. When transmitting a wireless signal, the optical-to-electrical converter 36-1-1 converts the optical signal output by the multiplexer / demultiplexer 53-1 into an electrical signal, which is then transmitted wirelessly from the antenna element 11-1-1. Although not shown, a similar configuration may be adopted for antenna elements 11 other than the antenna element 11-1-1. Furthermore, the section from the multiplexer / demultiplexer 55 to the beam control module 57 may also have a similar configuration.

[0076] Instead of the RF circulator 551 and optical circulator 554 shown in Fig. 5, a 1:2 RF switch and a 2:1 optical switch can be used as shown in Fig. 6. Fig. 6 shows another configuration of the portion indicated by the symbol A from the antenna element 11-1-1 to the electrical-optical / optical-electrical conversion unit 52-1-1 in Fig. 4. The antenna element 11-1-1 is connected to the electrical-optical conversion unit 12-1-1 and the optical-electrical conversion unit 36-1-1 via a 1:2 RF switch 561. The terminals of the multiplexer / demultiplexer 53-1 are connected to the electrical-optical conversion unit 12-1-1 and the optical-electrical conversion unit 36-1-1 via a 2:1 optical switch 565.

[0077] The 1:2 RF switch 561 has a first terminal 562 and second terminals 563-1 and 563-2. The first terminal 562 is connected to the antenna element 11-1-1, the second terminal 563-1 is connected to the electrical-to-optical converter 12-1-1, and the second terminal 563-2 is connected to the optical-to-optical converter 36-1-1. The 1:2 RF switch 561 switches whether the first terminal 562 is connected to the second terminal 563-1 or the second terminal 563-2 based on a TDD switching signal received from the beam control module 57. When receiving a radio signal, the beam control module 57 instructs the first terminal 562 to be connected to the second terminal 563-1 using the TDD switching signal, and when transmitting a radio signal, instructs the first terminal 562 to be connected to the second terminal 563-2 using the TDD switching signal.

[0078] The 2:1 optical switch 565 has first terminals 566-1 and 566-2 and a second terminal 567. The first terminal 566-1 is connected to the electrical-to-optical conversion unit 12-1-1, and the first terminal 566-2 is connected to the optical-to-electrical conversion unit 36-1-1. The second terminal 567 is connected to a terminal of the multiplexer / demultiplexer 53-1. The 2:1 optical switch 565 switches whether the first terminal 566-1 or the first terminal 566-2 is to be connected to the second terminal 567 based on a TDD switching signal received from the beam control module 57. When receiving a radio signal, the beam control module 57 instructs the first terminal 566-1 to connect to the second terminal 567 using the TDD switching signal, and when transmitting a radio signal, instructs the first terminal 566-2 to connect to the second terminal 567 using the TDD switching signal.

[0079] [Fourth Embodiment] The fourth embodiment is a configuration of a directivity control device for a receiver that imparts a phase tilt to a light source.

[0080] 7 is a diagram showing an example of the configuration of a directivity control device 7 according to this embodiment. The directivity control device 7 is a receiving directivity control device. In FIG. 7, the same components as those in the directivity control device 1 of the first embodiment shown in FIG. 1 are designated by the same reference numerals, and their description will be omitted.

[0081] The directivity control device 7 includes antenna elements 11-1-1 to 11-J-I, electrical-to-optical converters 12-1-1 to 12-J-I, light sources 73-1 to 73-K, a switching circuit 74, an optical matrix circuit 75, distributors 76-1 to 76-I, multiplexers 77-1 to 77-I, demultiplexers 78-1 to 78-K, electrical-to-electrical converters 79-1-1 to 79-K-I, and beam control modules 17-1 to 17-K. The following description will be given using an example where I=16, J=100, and K=10, where K is the number of beams.

[0082] As in the first embodiment, the two-dimensional array antenna 10 of the directivity control device 7 is configured by arranging 16 antenna elements 11 in the vertical direction and 100 antenna elements 11 in the horizontal direction on a grid.

[0083] The light sources 73-1 to 73-10 generate optical signals with carrier waves of different frequencies. The frequency of the optical signal generated by the light source 73-k is channel chk.

[0084] The switching circuit 74 has input terminals 741-1 to 741-10 and output terminals 742-1 to 742-100. The input terminal 741-k of the switching circuit 74 receives the light of channel chk from the light source 73-k. The switching circuit 74 outputs the light received from the input terminal 741-k from one of the output terminals 742-1 to 742-100 corresponding to the direction of the received beam. The directivity control device 7 can specify 100 horizontal directions for the received beam. The output terminals 742-1 to 742-100 correspond to the 100 horizontal directions of the received beam. The output terminals 742-1 to 742-100 from which the light received from the input terminal 741-k is output is determined, for example, based on information provided from outside the directivity control device 7. Such information can be obtained, for example, by performing a wireless communication beam search to find the direction in which the radio waves from the other station reach the strongest.

[0085] The optical matrix circuit 75 includes input terminals 751-1 to 751-100 and output terminals 752-1 to 752-100. An input terminal 751-k of the optical matrix circuit 75 is connected to an output terminal 742-k of the switching circuit 74. As a predetermined horizontal phase scanning process, the optical matrix circuit 75 imparts to each of the optical signals of different frequencies a phase gradient that offsets a horizontal phase gradient that occurs depending on differences in the positions of columns used during modulation by the electro-optical converter 12 and each desired direction, thereby generating an optical signal having the phase gradient for each frequency.

[0086] When an optical signal of channel chk is supplied from input terminal 751-k, optical matrix circuit 75 adds a horizontal phase tilt corresponding to received beam Bk to the 100 optical signals and outputs them from output terminals 752-1 to 752-100, respectively.

[0087] The distributor 76-j distributes into 16 optical signals the optical signal output from the output terminal 742-j of the optical matrix circuit 75. The distributor 76-j outputs each of the distributed optical signals to the electrical-to-optical converters 12-j-1 to 12-j-16 while maintaining the phase.

[0088] The electrical-to-optical converter 12-ji modulates the optical signal input from the distributor 76-j with the RF signal received by the antenna element 11-ji, thereby converting the received signal from an RF signal to an optical signal. The electrical-to-optical converter 12-ji inputs the converted optical signal to the multiplexer 77-i.

[0089] The multiplexer 77-i multiplexes the optical signals input from the electrical-to-optical converters 12-1-i to 12-100-i and outputs the multiplexed optical signal to the demultiplexer 78-i. The optical signals input to the demultiplexer 78-i are separated into optical signals of channels ch1 to ch10 according to their optical frequencies. The optical signals of channel chk separated by the demultiplexer 78-i are input to the optical-to-electrical converters 79-k-i. Each optical-to-electrical converter 79-k-i converts the optical signal of channel chk input from the demultiplexer 78-i into an electrical signal. The optical-to-electrical converter 79, for example, inputs the USB component of the input optical signal and an optical carrier signal that is separated from the USB component by the frequency (or IF) of the RF signal to a photodiode and converts them into an electrical signal (RF signal or IF signal).

[0090] The beam control module 17-k receives the electrical signals output from the photoelectric conversion units 79-1-k to 79-16-k and performs the same processing as in the first embodiment. That is, the beam control module 17-k electrically weights the received electrical signals using a phase tilt that depends on the in-plane direction of the vertical plane of the received beam Bk, and performs reception demodulation processing.

[0091] The directivity control device 7 detects the received beam Bk １ and receiving beam Bk ２ When receiving a radio signal of k, the following operation is performed: １ ≠k ２、 And k １ , k ２ is an integer between 1 and K. The two-dimensional array antenna 10 of the directivity control device 7 receives a beam Bk １ and receiving beam Bk ２ Each of the antenna elements 11-1-1 to 11-100-16 of the two-dimensional array antenna 10 outputs the received RF signal.

[0092] The switching circuit 74 is connected to the light source 73-k. １ The channel chk output by １ The optical signal is input to the input terminal 741-k. １ and input terminal 741-k １ Output terminal 742-k corresponding to ｋ１ (k ｋ１ is an integer between 1 and 100). ｋ１ The optical signal input from the antenna element 11 is affected by the difference in the horizontal position of the antenna element 11 and the received beam Bk １ The horizontal phase gradients are given opposite phases to the horizontal phase gradients that occur depending on the receiving direction of the signals, and are output from output terminals 742-1 to 742-100.

[0093] The switching circuit 74 also switches the light source 73-k ２ The channel chk output by ２ The optical signal is input to the input terminal 741-k. ２ and input terminal 741-k ２ Output terminal 742-k corresponding to ｋ２ (k ｋ２is an integer between 1 and 100). ｋ２ The optical signal input from the antenna element 11 is split into 100 signals, and the difference in the horizontal position of the antenna element 11 and the received beam Bk are calculated. ２ The horizontal phase gradients are applied in opposite phase to the horizontal phase gradients that occur depending on the receiving direction of the channel chk. １ Optical signal and channel chk ２ The optical signal is multiplexed with the optical signal of the first optical signal and output.

[0094] The distributors 76-1 to 76-100 distribute into 16 optical signals input from output terminals 752-1 to 752-100 of the optical matrix circuit 75. Each distributor 76-j, where j=1 to 100, outputs the distributed optical signals to electrical-to-optical converters 12-j-1 to 12-j-16 while maintaining the phase.

[0095] The electrical-to-optical converters 12-j-1 to 12-j-16 modulate the optical signals input from the distributor 76-j using the RF signals received by the antenna elements 11-j-1 to 11-j-16, respectively. For i=1 to 16, the electrical-to-optical converters 12-1-i to 12-100-i input the converted optical signals to the multiplexer 77-i.

[0096] Each multiplexer 77-i, where i=1 to 16, multiplexes the optical signals input from the electrical-to-optical conversion units 12-1-i to 12-100-i and outputs the multiplexed optical signal to the demultiplexer 78-i. The demultiplexers 78-1 to 78-16 separate the input optical signals into optical signals of channels ch1 to ch10. The demultiplexer 78-k inputs the separated optical signals of channels ch1 to ch10 to the optical-to-electrical conversion units 79-k-1 to 79-k-10, respectively. The optical-to-electrical conversion units 79-1-1 to 79-10-16 convert the input optical signals into electrical signals and output the converted electrical signals.

[0097] Beam control module 17-k １ is the photoelectric conversion unit 79-1-k １ ~79-16-k １ The electrical signal output from the receiving beam Bk is input. １The beam control module 17-k electrically weights the input electrical signal by a phase gradient that depends on the vertical plane direction of the beam control module 17-k, and performs reception demodulation processing. ２ is the photoelectric conversion unit 79-1-k ２ ~79-16-k ２ The electrical signal output from the receiving beam Bk is input. ２ The input electrical signal is electrically weighted by a phase gradient that depends on the vertical in-plane direction, and reception demodulation processing is performed.

[0098] Fifth Embodiment The fifth embodiment is directed to the use of a directivity control device for horizontal and vertical directions.

[0099] In the optical circuit, it is assumed that a variable phase shifter using the thermo-optic effect is used to change the phase shift amount or path switching. In this case, the time required to change the phase weighting in the optical weighting circuits 14, 34, 54 and the optical matrix circuit 75 is longer than the time required to change the phase weighting in the beam control modules 17, 31, 57.

[0100] For example, when the directivity control devices 1, 3, 5, and 7 according to the first to fourth embodiments described above are used in a base station 9 connected to a terminal station 8 moving on land, the time allowed for processing to change the beam direction in a vertical plane is often longer than the time allowed for processing to change the beam direction in a horizontal plane. This is because the beam direction in the vertical plane rarely changes at high speed in order to track the beam following the terminal station 8 moving on land.

[0101] In such a situation, beam scanning in the vertical plane, where slow scanning is permitted, can be performed by the optical weighting circuits 14, 34, 54 and the optical matrix circuit 75, and beam scanning in the horizontal plane, where fast scanning is required, can be performed by the beam control modules 17, 31, 57.

[0102] Planar lightwave circuits have the advantage of being able to construct compact matrix circuits with a large number of ports. Therefore, it is useful to apply optical circuit control to the plane that requires more branches in two orthogonal planes (vertical or horizontal).

[0103] In each of the above embodiments, an optical matrix circuit and an optical switching circuit are used as the optical weighting circuit, and the beam direction is selected by selecting the port (input terminal or output terminal) of the matrix circuit in the optical switching circuit, but the directivity control device according to this embodiment is not limited to this configuration. For example, the optical weighting circuit 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.

[0104] Furthermore, when a radio device capable of both transmission and reception is configured by combining a reception directivity control device with 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 transmission beam weighting value matrix and the reception beam weighting value matrix are the same due to differences in the installation position and installation direction of the transmission array antenna and the reception 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 realize 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.

[0105] The directivity control device of the above-described embodiment uses a two-dimensional beamformer to apply phase weighting to one of two orthogonal planes using optical applications, while applying phase weighting to the other plane using conventional electronic circuit control. By using an optical phase shift circuit, optical wavelength multiplexing is performed within the circuit, enabling multiple beam signals to be processed using a single optical phase shift circuit. Furthermore, the plane requiring more branches to be phase-controlled is controlled using optical circuit applications, while the other plane is controlled using conventional electronic circuit control. This allows for a significant expansion in the number of controllable antenna elements by externally attaching the device to an existing electronic circuit-based beamformer, thereby providing a directivity control device capable of controlling multi-element multibeams. However, when shared use is required for transmitting and receiving antennas, time-division switching is required. This embodiment can prevent an increase in the number of beamforming circuit components and a complex structure. Furthermore, the directivity control device can be configured without using a three-dimensional structure.

[0106] As described above, according to this embodiment, the number of antenna elements that can be controlled by an existing electronic circuit-type directivity control circuit is significantly expanded, and a directivity control device capable of controlling multi-element multi-beams is provided. Furthermore, wavelength multiplexing prevents an increase in the number of components constituting the weighting circuit and a complex structure, making it possible to control the directivity of a multi-element phased array antenna without significantly increasing the number of circuit components. Furthermore, since the number of components and wiring points can be reduced, a device suitable for mass production and miniaturization can be provided.

[0107] According to the above-described embodiment, the directivity control device includes an antenna unit, a first weighting unit, and a second weighting unit. The antenna unit corresponds to, for example, the two-dimensional array antennas 10, 30, and 50 of the embodiments. The antenna unit has a plurality of antenna elements arranged at positions where a plurality of parallel first lines intersect with a plurality of parallel second lines perpendicular to the first lines on a plane. The first weighting unit corresponds, for example, to the electro-optical converter 12, the multiplexer 13, and the optical weighting circuit 14 of the embodiments. Also, for example, the first weighting unit corresponds to the electro-optical / photoelectric converter 52, the multiplexer / demultiplexer 53, and the optical weighting circuit 54 of the embodiments. The first weighting unit converts the radio signals received by each antenna element into first optical signals and assigns weights to the converted first optical signals to offset phase differences that occur depending on the difference in the positions of the antenna elements in the first line direction (on the first line) and the reception direction of the radio signals. The second weighting unit corresponds to, for example, the demultiplexer 15, the photoelectric conversion unit 16, and the beam control module 17 in the embodiments. The second weighting unit also corresponds to, for example, the multiplexer / demultiplexer 55, the electro-optical / photoelectric conversion unit 56, and the beam control module 57 in the embodiments. The second weighting unit converts the weighted first optical signal into a first electrical signal, and weights the converted first electrical signal to offset a phase difference that occurs depending on the difference in position of the antenna element in the second linear direction (on the second straight line) and the receiving direction.

[0108] The directivity control device may receive and transmit radio signals in a time-division manner. When transmitting the radio signals, the second weighting unit weights the second electrical signals to be transmitted, imparting a phase difference that depends on the position of the antenna elements on the second straight line and the transmission direction of the radio signals, and converts the weighted second electrical signals into second optical signals. When transmitting the radio signals, the first weighting unit weights the converted second optical signals, imparting a phase difference that depends on the position of the antenna elements on the first straight line and the transmission direction, and converts the weighted second optical signals into third electrical signals and transmits them wirelessly from the multiple antenna elements.

[0109] The first weighting unit may include a first conversion unit, a first multiplexing / demultiplexing unit, and an optical weighting unit, and the second weighting unit may include a second multiplexing / demultiplexing unit, a second conversion unit, and a beam control unit. When receiving a radio signal, the first conversion unit converts the radio signal received by each antenna element into a first optical signal of a channel having a frequency corresponding to the position of the antenna element in the second linear direction. The first multiplexing / demultiplexing unit multiplexes the first optical signal for each second linear antenna element group consisting of antenna elements located on the same second linear direction, i.e., antenna elements located at the same position in the first linear direction, to generate an optical multiplexed received signal. The optical weighting unit applies weighting to the optical multiplexed received signal to offset phase differences that occur depending on the position of the antenna elements in the first linear direction and the direction of reception of the radio signal. The second multiplexing / demultiplexing unit demultiplexes the weighted optical multiplexed received signal into optical received signals for each channel. The second conversion unit converts the optical received signal into a first electrical signal. The beam control unit weights the first electrical signal for each receiving direction to offset differences in the positions of the antenna elements in the second linear direction and differences in phase that occur depending on the receiving direction.

[0110] When the directivity control device transmits a radio signal, the beam control unit weights second electrical signals corresponding to the respective positions of the antenna elements in the second linear direction for each transmission direction of the radio signal, imparting a phase difference corresponding to the difference in the positions of the antenna elements in the second linear direction and the transmission direction. The second conversion unit converts each weighted second electrical signal into a second optical signal of a channel corresponding to the position in the second linear direction of the antenna element transmitting the second electrical signal. The second multiplexing / demultiplexing unit generates an optical multiplexed transmission signal by multiplexing the second optical signal for each transmission direction. The optical weighting unit distributes the optical multiplexed transmission signal into optical multiplexed transmission signals corresponding to each of the second linear antenna element group, and weights each distributed optical multiplexed transmission signal to impart a phase difference corresponding to the difference in the positions of the antenna elements in the first linear direction and the transmission direction. The first multiplexing / demultiplexing unit demultiplexes each weighted optical multiplexed transmission signal into an optical transmission signal for each channel. The first conversion unit converts each optical transmission signal into a third electrical signal, and transmits the converted third electrical signal wirelessly from an antenna element included in a second linear antenna element group corresponding to the optical multiplexed transmission signal from which the third electrical signal was obtained, and at a position in the second linear line corresponding to the channel before conversion.

[0111] The first weighting unit may assign weights to multiple light beams obtained by splitting light beams for channels corresponding to the receiving direction, based on the opposite phases of the phases that occur depending on the difference in the positions of the antenna elements in the first linear direction and the receiving direction of the radio signal, and generate weighted first optical signals by modulating the weighted light beams with the radio signals received by each of the antenna elements. The first weighting unit generates an optical multiplexed signal by multiplexing the generated first optical signals for each group of antenna elements located on the same second linear direction. In this case, for example, the first weighting unit corresponds to the electrical-to-optical conversion unit 12, the light sources 73-1 to 73-10, the switching circuit 74, the optical matrix circuit 75, the distributors 76-1 to 76-100, and the multiplexers 77-1 to 77-16 of the embodiment. The second weighting unit demultiplexes each optical multiplexed signal into second optical signals for each channel, converts each demultiplexed second optical signal into a first electrical signal, and weights the first electrical signal obtained from the second optical signal of each channel corresponding to the receiving direction so as to offset a difference in phase that occurs depending on the difference in position of the antenna element in the second linear direction and the receiving direction. In this case, for example, the second weighting unit corresponds to the demultiplexers 78-1 to 78-16, the photoelectric conversion units 79-1-1 to 79-10-16, and the beam control module 17 in the embodiment.

[0112] The first weighting unit may include an optical weighting unit, an electrical-to-optical converter, and a multiplexing unit, and the second weighting unit may include a demultiplexing unit, an optical-to-electrical converter, and a beam control unit. The optical weighting unit branches light of a channel corresponding to the reception direction of the radio signal into light corresponding to each of a second linear antenna element group consisting of antenna elements located on the same second straight line, and weights the branched light using an inverse phase of the phase that occurs depending on the difference in the positions of the antenna elements in the first straight line direction and the reception direction of the radio signal. For each second linear antenna element group, the electrical-to-optical converter modulates the light corresponding to the second linear antenna element group and weighted by the optical weighting unit with a first electrical signal received by the antenna element belonging to the second linear antenna, to generate a first optical signal. For each first antenna element group consisting of antenna elements located on the same first straight line direction, the multiplexing unit generates an optical multiplexed reception signal by multiplexing the first optical signal converted by the electrical-to-optical converter. The demultiplexing unit demultiplexes each optical multiplexed reception signal into an optical reception signal for each channel. The optical-to-electrical converter converts each optical reception signal into a second electrical signal. The beam control unit weights the second electrical signal obtained from the optical reception signal of the channel corresponding to each reception direction to offset the difference in position of the antenna element in the second linear direction and the difference in phase that occurs depending on the reception direction.

[0113] A device that transmits a wireless signal received by the antenna unit moves faster in the direction of the first straight line than in the direction of the second straight line. The device that transmits the wireless signal corresponds to, for example, the terminal station 8 in the embodiment.

[0114] According to the above-described embodiment, the directivity control device includes an antenna unit, a first weighting unit, and a second weighting unit. The antenna unit has a plurality of antenna elements arranged at positions where a plurality of parallel first lines and a plurality of parallel second lines perpendicular to the first lines intersect on a plane. The first weighting unit corresponds, for example, to the beam control module 31 and the electrical-to-optical converter 32 in the embodiments. The first weighting unit weights a first electrical signal to be transmitted, imparting a phase difference corresponding to the difference in the position of the antenna elements in the first line direction and the transmission direction of the wireless signal, and converts the weighted first electrical signal into an optical signal. The second weighting unit corresponds, for example, to the multiplexer 33, the optical weighting circuit 34, the demultiplexer 35, and the optical-to-electrical converter 36 in the embodiments. The second weighting unit weights the converted optical signal, imparting a phase difference corresponding to the difference in the position of the antenna elements in the second line direction and the transmission direction, and converts the weighted optical signal into a second electrical signal and transmits it wirelessly from the plurality of antenna elements. A device receiving radio waves from this directivity control device moves faster in the direction of the second straight line than in the direction of the first straight line.

[0115] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configurations are not limited to these embodiments, and include designs within the scope of the present invention that do not deviate from the gist of the present invention.

[0116] 1, 3, 5, 7 Directivity control device 8 Terminal station 9 Base station 10, 30 Two-dimensional array antenna 11-1-1 to 11-100-16 Antenna element 12-1-1 to 12-100-16 Electrical-optical conversion unit 13-1 to 13-100 Multiplexer 14 Optical weighting circuit 15-1 to 15-10 Demultiplexer 16-1-1 to 16-10-16 Optical-electrical conversion unit 17-1 to 17-10 Beam control module 31-1 to 31-10 Beam control module 32-1-1 to 32-10-16 Electrical-optical conversion unit 33-1 to 33-10 Multiplexer 34 Optical weighting circuit 35-1 to 35-100 Demultiplexer 36-1-1 to 36-100-16 Optical-electrical conversion unit 37-1-1 to 37-100-16 Antenna elements 52-1-1 to 52-100-16 Electrical-optical / optical-electrical conversion section 53-1 to 53-100 Multiplexer / demultiplexer 54 Optical weighting circuit 55-1 to 55-10 Multiplexer / demultiplexer 56-1-1 to 56-10-16 Electrical-optical / optical-electrical conversion section 57-1 to 57-10 Beam control module 73-1 to 73-10 Light source 74 Switching circuit 75 Optical matrix circuit 76-1 to 76-100 Distributor 79-1-1 to 79-10-16 Optical-electrical conversion section 141 Optical matrix circuit 142-1 to 142-100 Input terminal 143-1 to 143-100 Output terminal 145 Optical switching circuit 146-1 to 146-100 Input terminals 147-1 to 147-100 Output terminals 342-1 to 342-10 Input terminals 347-1 to 347-100 Output terminals 542-1 to 542-100 First terminals 547-1 to 547-10 Second terminals 551 RF circulator 554 Optical circulator 561 1:2 RF switch 562 First terminal 563-1, 563-2 Second terminals 565 2:1 optical switch 566-1, 566-2 First terminals 567 Second terminals 741-1 to 741-10 Input terminals 742-1 to 742-100 Output terminals 751-1 to 751-100 Input terminals 752-1 to 752-100 Output terminals

Claims

1. A directivity control device comprising: an antenna unit having a plurality of antenna elements arranged at respective positions on a plane where a plurality of parallel first lines and a plurality of parallel second lines perpendicular to the first lines intersect; a first weighting unit that converts radio signals received by each of the antenna elements into a first optical signal and assigns weighting to the converted first optical signal to offset a phase difference that occurs depending on a difference in the position of the antenna elements in the direction of the first lines and a receiving direction of the radio signal; and a second weighting unit that converts the weighted first optical signal into a first electrical signal and assigns weighting to the converted first electrical signal to offset a phase difference that occurs depending on a difference in the position of the antenna elements in the direction of the second line and a receiving direction.

2. The directivity control device according to claim 1, wherein the directivity control device receives and transmits radio signals in a time-division manner, and when transmitting a radio signal, the second weighting unit weights the second electrical signal to be transmitted to impart a phase difference that depends on the difference in position of the antenna element in the second linear direction and the transmission direction of the radio signal, and converts the weighted second electrical signal into a second optical signal, and the first weighting unit weights the converted second optical signal to impart a phase difference that occurs depending on the difference in position of the antenna element in the first linear direction and the transmission direction, and converts the weighted second optical signal into a third electrical signal and transmits it wirelessly from a plurality of the antenna elements.

3. The directivity control device according to claim 1, wherein the first weighting unit weights a plurality of lights obtained by splitting light of a channel corresponding to the receiving direction by an inverse phase of a phase that occurs depending on a difference in position of the antenna elements in the first linear direction and the receiving direction of the radio signal, generates the weighted first optical signal by modulating the weighted light with a radio signal received by each of the antenna elements, and generates an optical multiplexed signal by multiplexing the generated first optical signals for each of the antenna element groups located on the same second linear line; the second weighting unit demultiplexes each of the optical multiplexed signals into second optical signals for each of the channels, converts each of the demultiplexed second optical signals into a first electrical signal, and weights the first electrical signal obtained from the second optical signal of each of the channels corresponding to the receiving direction so as to offset a phase difference that occurs depending on a difference in position of the antenna elements in the second linear direction and the receiving direction.

4. A directivity control device according to any one of claims 1 to 3, wherein a device that transmits the radio signal received by the antenna unit moves faster in the direction of the first straight line than in the direction of the second straight line.

5. A directivity control device comprising: an antenna section having a plurality of antenna elements arranged at positions on a plane where a plurality of parallel first lines intersect with a plurality of parallel second lines perpendicular to the first lines; a first weighting section that weights a first electrical signal to be transmitted to impart a phase difference that depends on the difference in the positions of the antenna elements on the first line and the transmission direction of a radio signal, and converts the weighted first electrical signal into an optical signal; and a second weighting section that weights the converted optical signal to impart a phase difference that occurs depending on the difference in the positions of the antenna elements on the second line and the transmission direction, converts the weighted optical signal into a second electrical signal, and transmits it wirelessly from the plurality of antenna elements.

6. The directivity control device according to claim 5, wherein the device receiving the radio waves moves faster in the direction of the second straight line than in the direction of the first straight line.

7. A directivity control method comprising: a first weighting step of converting a radio signal received by each of the antenna elements of an antenna unit having a plurality of antenna elements arranged at each of the positions where a plurality of parallel first lines and a plurality of parallel second lines perpendicular to the first lines intersect on a plane, into a first optical signal, and assigning to the converted first optical signal a weighting that offsets a phase difference that occurs depending on a difference in position of the antenna elements in the first line direction and a receiving direction of the radio signal; and a second weighting step of converting the weighted first optical signal into a first electrical signal, and assigning to the converted first electrical signal a weighting that offsets a phase difference that occurs depending on a difference in position of the antenna elements in the second line direction and a receiving direction.

8. A directivity control method comprising: a first weighting step of weighting a first electrical signal to be transmitted based on a phase difference occurring depending on the difference in the positions of the antenna elements on the first straight line and the transmission direction of a radio signal in an antenna unit having a plurality of antenna elements arranged at positions where a plurality of parallel first straight lines intersect with a plurality of parallel second straight lines perpendicular to the first straight lines on a plane, and converting the weighted first electrical signal into an optical signal; and a second weighting step of weighting the converted optical signal based on a phase difference occurring depending on the difference in the positions of the antenna elements on the second straight line and the transmission direction, converting the weighted optical signal into a second electrical signal and transmitting it wirelessly from the plurality of antenna elements.

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