JPH0659008B2 - Optically controlled phased array antenna - Google Patents

Description

The present invention relates to an optically controlled phased array antenna.

[Prior Art] In recent years, as a land mobile station antenna and satellite antenna for automobiles of mobile satellite communication systems, the antenna is small and lightweight, can withstand vibration, and has a wide angle for tracking a partner station. There is a demand for a high-performance and highly-functional antenna that can perform beam scanning at high speed and can form a beam pattern having a desired shape according to communication conditions. These requirements are generally transmitted and received using the plurality of antennas so that the beam direction becomes a desired direction in a phased array antenna in which a plurality of antennas are juxtaposed for beam scanning that changes the radiation direction. Each transmission signal or each reception signal that excites the plurality of antennas in order to appropriately shift the phase of each transmission signal or each reception signal (hereinafter referred to as phase shift) and to form a desired beam pattern. This can be realized by appropriately weighting the amplitude of (hereinafter, referred to as weighting of signal amplitude). For example, assuming that a transmission signal having a transmission frequency ωr output from a transmitter is represented by the following equation, cosωrt (1) The excitation current output to a plurality of n antennas in a phased array antenna is represented by the following equation. Need to do so.

Akcos (ωrt + θk), k = 1, 2, 3, ..., N (2) Here, Ak is an amplitude coefficient given to the excitation current of each antenna to form a desired beam pattern, and θk
Is the amount of phase shift given to the excitation current of each antenna to obtain the desired beam direction. Therefore, a transmission phased array antenna is formed by forming each excitation current represented by the above formula (2) capable of independently controlling Ak and θn from the transmission signal and outputting each excitation current to each antenna. Can be configured.

FIG. 4 is a block diagram of a conventional transmission phased array antenna device.

In FIG. 4, the semiconductor laser diode 31 outputs coherent light to the beam splitter 32. The beam splitter 32 splits the incident light into two, outputs one of the split lights to the optical frequency shifter 33, and
The other light is output to the mask 37 via the mirror 36.
For example, a high frequency signal of 100 MHz, which is frequency-modulated by a baseband signal, is transmitted from the transmitter 41 to an optical frequency shifter 33 including an acousto-optic device (AOM).
In response to this, the optical frequency shifter 33 shifts the wavelength of the incident light by the frequency of the input high frequency signal, and outputs it to the spatial filter 35 via the mirror 34. The spatial filter 35 collimates the incident light into parallel light and collimates the light into a beam splitter 39.
Output to.

The mask 37 has a light transmittance distribution of a pattern obtained by Fourier-transforming the radiation pattern distribution of the high frequency signal radiated from the antennas 45a to 45e, and converts the incident light into light having the intensity distribution of the pattern. The light is output to the beam splitter 39 via the collimator lens 38. Here, the collimator lens 38 is located between the mask 37 and the beam splitter 39, and is located at a position where the distribution of the light output from the mask 37 is optically inversely Fourier-transformed so that the light enters the beam splitter 39. It is provided in.

The beam splitter 39 multiplexes the two incident lights and outputs them to the condenser lens array 40. The condensing lens array 40 has condensing lenses of the same number as the antennas 43a to 43e having the same light receiving area, and collects the light incident from the beam splitter 39 by the condensing lenses. The light is emitted and the photoelectric converters 43a to 4 are respectively transmitted through the optical fiber cables 42a to 42e.
Output to 3e.

The laser diode 31 and the beam splitter 3
2, 39, the optical frequency shifter 33, the mirrors 34 and 36, the mask 37, the collimating lens 38, and the condenser lens array 40 can block the light other than the light output from the laser diode 31 from entering from the outside. It is accommodated in 30.

Each of the photoelectric converters 43a to 43e is composed of, for example, a photodiode, detects each input light,
Five high-frequency signals obtained by detection are arranged in a row through the power amplifiers 44a to 44e to form five antennas 45.
a to 45e are output and emitted. Here, the radiation pattern of the antenna in the far field of the high-frequency signal radiated from the antennas 45a to 45e corresponds to the light transmittance distribution of the mask 37. Because, as shown in FIG. 5, the radiation pattern of the antenna in the far field is
5a to 45e, the current distribution on the aperture surface of the antenna is free-converted, and since the polarization plane is held from the lens array 40 to the photoelectric converters 43a to 43e, the current distribution on the antenna aperture surface is Corresponds to the light intensity (power) distribution on the light-receiving surface of the lens array 40, and the light intensity (power) distribution on the light-receiving surface of the lens array 40 is inversely free-transformed with respect to the light transmittance distribution of the mask 37. This is because it is a pattern.

In the transmission phased array antenna configured as described above, the signal amplitude can be weighted as described above by changing the light transmittance distribution of the mask 37, so that the antenna radiation pattern in the far field is changed. can do. Further, by slightly shifting the mask 37 in a direction perpendicular to the optical axis, an optical path difference is provided to each light until the light output from the mirror 36 enters each condenser lens of the condenser lens array 40. Since it can be generated, a phase difference of each light received by each condensing lens of the condensing lens array 40 is generated, and thereby the above phase shift can be performed. Therefore, by weighting the signal amplitude and shifting the phase, the radiation pattern can be changed and the beam can be scanned in the phased array antenna.

[Problems to be Solved by the Invention] In the phased array antenna described above, the housing 30
Since the Mach-Zehnder type optical interferometer composed of the optical devices 31 to 39 housed therein is included, it is possible to highly accurately combine each light split into two lights by using the beam splitter 39. It is necessary to align the optical axis of each light.
Therefore, it is difficult to operate the optical interferometer in an environment where even a slight vibration exists. In addition, as described above, since the large number of optical devices 31 to 39 are included, the shape of the device becomes relatively large.

Further, in the above-mentioned phased array antenna, the phase shift is realized by shifting the mask 37 in the direction perpendicular to the optical axis. This method is used to collect light at each condenser lens of the condenser lens array 40. There is a problem in that the optical path difference between the emitted lights cannot be realized with high accuracy, and thus it is difficult to perform desired beam scanning required for the antenna.

Therefore, it is unsuitable to use the phased array antenna of the above-mentioned conventional example as an antenna for a mobile body or a satellite, which is required to be small and lightweight and to have stable characteristics that are not affected by vibration.

Furthermore, since the optical frequency shifter 33 is composed of the acousto-optic device as described above, the frequency of the incident light can be shifted by the frequency of the high frequency signal in the VHF band up to about 300 MHz. The frequency shifter 33 cannot be operated at a higher frequency, for example, in the microwave band. Therefore, the phased array antenna described above cannot be excited at a frequency higher than the microwave band.

The object of the present invention is to solve the above problems and to perform beam scanning by performing the above phase shift with high accuracy, and is smaller and lighter than the conventional example and used at frequencies in the microwave band or higher. Another object of the present invention is to provide a phased array antenna that can be operated and is not easily affected by vibration.

[Means for Solving the Problems] An optically controlled transmission phased array antenna according to the present invention is an optical signal generation means for generating a coherent optical signal in a transmission phased array antenna including a plurality of antennas (7a-7e). (11) and the optical signal output from the optical signal generating means (11) is divided into a plurality of optical signals each having an optical intensity corresponding to a predetermined far-field radiation pattern of the transmission phased array antenna. 1 distribution means (12, 13), a transmission signal output means (1) for outputting a transmission signal, and the transmission signal output means (1)
Second distribution means (2) for distributing the transmission signal output from the plurality of transmission signals, and the first distribution means (12, 1)
3) a plurality of optical signals output from the first distribution means (12, 13)
Of the plurality of first optical signals and the plurality of second optical signals so that the optical signal and the second optical signal can be divided into two. ) And a plurality of first optical signals output from the plurality of third distributing means (21 of 4a-4e), and a frequency of a plurality of transmission signals output from the second distributing means (2). Optical frequency shifter means (4a-4e, 2
5) and the plurality of third distribution means (2 of 4a-4e).
A plurality of optical phase shifting means (22 of 4a-4e) for respectively shifting the plurality of second optical signals output from 1) by the respective phase shift amounts corresponding to the beam directions of the input transmission phased array antennas. ), A plurality of first optical signals output from the plurality of optical frequency shifter means (25 of 4a-4e), and a plurality of first optical signals output from the plurality of optical phase shift means (22 of 4a-4e). A plurality of multiplexing means (23 of 4a-4e) for multiplexing the second optical signal for each corresponding pair.
And a plurality of photoelectric conversion means (5a-) that detect a plurality of optical signals output from the plurality of multiplexing means (23 of 4a-4e) and output transmission signals to the plurality of antennas (7a-7e), respectively. 5e), whereby a plurality of transmission signals output from the plurality of photoelectric conversion means (5a-5e) are radiated from the antennas (7a-7e), respectively.

Further, the optically controlled reception phased array antenna according to the present invention includes a plurality of antennas (50a-) for receiving reception signals.
50e) in a receiving phased array antenna, an optical signal generating means (11) for generating a coherent optical signal and an optical signal output from the optical signal generating means (11) are supplied to a predetermined phase of the receiving phased array antenna. First distributing means (12, 1) for distributing to a plurality of optical signals each having an optical intensity corresponding to the reception pattern of the far field of
3) and a plurality of optical signals output from the first distributing means (12, 13) are transferred to the first distributing means (12, 1).
3) a plurality of first optical signals and a plurality of second optical signals so that each optical signal output from 3) is divided into a pair of a first optical signal and a second optical signal. The plurality of fourth distributing means (21 of 4a-4e) for distributing, and the plurality of first optical signals output from the plurality of fourth distributing means (21 of 4a-4e), the plurality of antennas. A plurality of optical frequency shifter means (2 of 4a-4e) for respectively frequency-shifting only the frequencies of the plurality of transmission signals output from (50a-50e).
5) and the plurality of fourth distributing means (2 of 4a-4e)
A plurality of optical phase shifting means (22 of 4a-4e) for respectively shifting the plurality of second optical signals output from 1) by the respective phase shift amounts corresponding to the beam directions of the input reception phased array antennas. ), A plurality of first optical signals output from the plurality of optical frequency shifter means (25 of 4a-4e), and a plurality of first optical signals output from the plurality of optical phase shift means (22 of 4a-4e). A plurality of multiplexing means (23 of 4a-4e) for multiplexing the second optical signal for each corresponding pair.
And a combining means (52) for combining a plurality of optical signals output from the plurality of combining means (23 of 4a-4e), and an optical signal output from the combining (52). A photoelectric conversion means (53) for outputting a reception signal is provided.

[Operation] In the optically controlled transmission phased array antenna configured as the former, the first distribution means (12, 1)
3) distributes the optical signal output from the optical signal generating means (11) into a plurality of optical signals each having a light intensity corresponding to a predetermined far-field radiation pattern of the transmission phased array antenna. On the other hand, the second distribution means (2) distributes the transmission signal output from the transmission signal output means (1) into a plurality of transmission signals. Then, the plurality of third distributing means (21 of 4a-4e) are connected to the first
Of the plurality of optical signals output from the first distributing means (12, 13), each optical signal output from the first distributing means (12, 13) is a pair of the first optical signal and the second optical signal. The signal is divided into a plurality of first optical signals and a plurality of second optical signals so as to be divided into two. Further, the plurality of frequency shifter means (25 of 4a-4e) distributes the plurality of first optical signals output from the plurality of third distribution means (21 of 4a-4e) to the second distribution means. The frequency shift is performed by the frequencies of the plurality of transmission signals output from the means (2). On the other hand, the plurality of optical phase shifting means (22 of 4a-4e) receives the plurality of second optical signals output from the plurality of third distributing means (21 of 4a-4e). The phase is shifted by the phase shift amount corresponding to the beam direction of the transmitting phased array antenna. Further, the plurality of multiplexing means (23 of 4a-4e) are provided with the plurality of first optical signals output from the plurality of optical frequency shifter means (25 of 4a-4e) and the plurality of optical phase shifts. The plurality of second optical signals output from the means (22 of 4a-4e) are multiplexed for each corresponding pair, and then the plurality of photoelectric conversion means (5a-).
5e) detects a plurality of optical signals output from the plurality of multiplexing means (23 of 4a-4e) and outputs a transmission signal to each of the plurality of antennas (7a-7e). Thereby, the plurality of transmission signals output from the plurality of photoelectric conversion means (5a-5e) are transmitted to the antenna (7a-7e).
Radiate from each. Therefore, the plurality of optical phase shifters (22 of 4a-4e) change the respective phase shift amounts corresponding to the beam directions of the transmission phased array antennas to control the beam directions. An array antenna can be constructed.

In the optically controlled reception phased array antenna configured as the latter, the first distribution means (12, 1) is used.
3), after dividing the optical signal output from the optical signal generating means (11) into a plurality of optical signals each having an optical intensity corresponding to a predetermined far field reception pattern of the reception phased array antenna, The plurality of fourth distributing means (21 of 4a-4e) are the first distributing means (12, 1).
3) and a plurality of optical signals output from the first distributing means (12, 13) are transferred to the first distributing means (12, 1).
3) a plurality of first optical signals and a plurality of second optical signals so that each optical signal output from 3) is divided into a pair of a first optical signal and a second optical signal. Distribute. Then, the plurality of optical frequency shifter means (25 of 4a-4e) outputs the plurality of first optical signals output from the plurality of fourth distributing means (21 of 4a-4e) to the plurality of antennas. (50
a-50e) frequency-shifts only the frequencies of the plurality of transmission signals. On the other hand, the plurality of optical phase shifting means (22 of 4a-4e) outputs from the plurality of optical frequency shifter means (25 of 4a-4e) and the plurality of fourth distributing means (21 of 4a-4e). The plurality of second optical signals to be input are phase-shifted by the respective phase-shifting amounts corresponding to the beam directions of the input reception phased array antenna. Further, the plurality of first multiplexing means (23 of 4a-4e) are the plurality of optical frequency shifter means (4a-4e).
No. 25) of the plurality of first optical signals and a plurality of second optical signals output from the plurality of optical phase shifters (22 of 4a-4e), for each corresponding pair. After multiplexing, the second multiplexing means (52) is arranged to
The multiple optical signals output from the multiplexing means (23 of 4a-4e) are multiplexed. Then, the photoelectric conversion means (53)
Detects the optical signal output from the second multiplexing means (52) and outputs a reception signal. Therefore, the plurality of optical phase shifters (22 of 4a-4e) change each phase shift amount corresponding to the beam direction of the receive phased array antenna, thereby controlling the beam direction. An array antenna can be constructed.

[Embodiment] First Embodiment FIG. 1 is a block diagram of an optically controlled transmission phased array antenna according to a first embodiment of the present invention.

In the optically controlled transmission phased array antenna of the first embodiment, the frequencies of the five optical control signals corresponding to the radiation pattern output from the optical control signal generator 10 are output from the transmitter 1 to 5 frequencies. An optical control type shifter having an optical frequency shifter 25 for shifting the frequency of the distributed microwave signal and an optical phase shifter 22 for controlling the phase of each optical control signal by the DC voltage output from the variable voltage source 17. The phase shifters 4a to 4e are provided.

In FIG. 1, the transmitter 1 frequency-modulates a microwave signal of a predetermined frequency with an input baseband signal, and then outputs the microwave signal to the distributor 2. The distributor 2 divides the input microwave signal into five parts so that the power of the distributed microwave signal is equally divided, and the distributed microwave signals are optically transmitted through the amplifiers 3a to 3e, respectively. It outputs to the control type phase shifters 4a to 4e.

The optical control signal generator 10 includes a semiconductor laser diode 11
A mask 12, a collimator lens 13, and a condenser lens array 14, in which each optical device 11 to 14 can block light other than the light output from the laser diode 11. Housed in. The semiconductor laser diode 10 outputs coherent light having a predetermined wavelength to the condenser lens array 14 via the mask 12 and the collimator lens 13.

The mask 12 has a transmittance distribution corresponding to the radiation pattern of the antenna in the far field similarly to the conventional example, and is made of, for example, chrome in a region that blocks light on the plate surface of a glass plate having a transmittance of 1. It is configured by applying a black light blocking material.
Here, the transmittance of the region on the glass plate surface coated with the light blocking material is approximately 0, while the transmittance of the region on the glass plate surface not coated with the light blocking material is 1. . Therefore, the coherent light output from the laser diode 11 is output to the collimator lens 13 via the area of the mask 12 having the transmittance of 1. The collimator lens 13 collimates the incident light into parallel light and outputs the collimated light to the condenser lens array 14. Here, the collimator lens 13 is located between the mask 12 and the condenser lens array 14, and the distribution of the light output from the mask 12 is optically inverse Fourier transformed so that the light is condensed. It is provided at such a position as to be incident on.

The condenser lens array 14 has condenser lenses of the same number as the antennas 7a to 7e having the same light receiving area, and collects the incident light by the condenser lenses. Polarization maintaining optical fiber cable 15
It outputs to the light control type phase shifters 4a to 4e via a to 15e, respectively.

As shown in FIG. 2, each of the light control type phase shifters 4a to 4e has a branching optical waveguide 21, an optical phase shifter 22, 24, and a multiplexing optical waveguide 23 formed on a dielectric substrate 20, respectively. , The optical frequency shifter 25, and the optical waveguides 61 to 6
7, each of the light control type phase shifters 4a to 4e is similarly configured. In the light control type phase shifters 4a to 4e, the respective lights output from the respective condenser lenses of the condenser type lens array 14 are respectively transmitted through the polarization maintaining optical fiber cables 15a to 15e. After being incident on the input end 60 of each of the containers 4 a to 4 e, it is incident on the input end of the branch optical waveguide 21 via the optical waveguide 61. The branched optical waveguide 21 divides the incident light into two so that the intensity of the distributed light is evenly divided, and one of the distributed light is divided into the optical waveguide 62, the optical phase shifter 22, and the optical waveguide 63. The output light is output to the second input end of the multiplexing optical waveguide 23 via the optical waveguide 64, the optical phase shifter 24, the optical waveguide 65, the optical frequency shifter 25, and the optical waveguide 66. And outputs to the first input end of the multiplexing optical waveguide 23. The multiplexing optical waveguide 23 multiplexes the respective lights incident on the first input end and the second input end, respectively, and combines the lights into the optical waveguide 67, the output ends 68 of the light control type phase shifters 4a to 4e, and the light. Photoelectric converters 5a to 5 via fiber cables 19a to 19e
output to e.

Each of the optical phase shifters 22 and 24 has an electrode for applying an electric field in a direction perpendicular to the optical axis of the linear optical waveguide, and the electrode is connected to the variable voltage sources 16 and 17. Therefore, a predetermined DC voltage output from the variable voltage sources 16 and 17 is applied to each electrode of the optical phase shifters 22 and 24, and a predetermined DC voltage is applied to the light traveling through the optical waveguides in the optical phase shifters 22 and 24. Is applied to shift the phase of the advancing light by a predetermined phase shift amount. Here, the optical phase shifter 22 is for performing the above-mentioned phase shift.
The variable voltage source 1 for supplying a DC voltage for controlling the amount of phase shift to the
7 is connected to a direction control device 18 for controlling the beam direction of this phased array antenna.
8 is connected to an input device 80 for inputting the information on the beam direction. Further, the optical phase shifter 24 corrects each light divided into two at the branching portion of the branching optical waveguide 21 so that the respective optical path differences until reaching the multiplexing portion of the above-mentioned multiplexing optical waveguide 23 become equal. Is a phase shifter for phase correction.

The optical frequency shifter 25 shifts the wavelength of the light incident through the optical waveguide 65 by the frequency of the microwave signal input from the amplifiers 3a to 3e, and then multiplexes it through the optical waveguide 66. The signal is output to the first input terminal of the waveguide 23. The optical frequency shifter 25 is composed of a plurality of optical phase shifters each having the same configuration as the above optical phase shifters 22 and 24. The configuration of the optical frequency shifter 25 is described in, for example, "Integration by Masayuki Izutsu et al. Optical SSB Modulator / Frequency Shifter ", IEEE Journal of Quantum Electronics, Vol. QE-17, N
o. 11, November 1981, pages 2225 to 22
It is disclosed on page 28.

Each of the photoelectric converters 5a to 5e is, for example, a PIN photodiode or an avalanche photodiode and has a square-law detection characteristic. The photoelectric converters 5a to 5e detect each input light and remove a DC component, and then detect the above-mentioned detection. The respective microwave signals obtained by the above are output to the five antennas 7a to 7e arranged in a line through the power amplifiers 6a to 6e to be radiated. Here, the radiation pattern of the microwave signals radiated from the antennas 7 a to 7 e in the far field of the antenna corresponds to the light transmittance distribution of the mask 12. This is because the radiation pattern of the antenna in the far field is similar to that of the conventional example.
Is a pattern obtained by performing a free conversion on the current distribution on the aperture plane in FIG. 6 and the polarization plane is held from the condenser lens array 14 to the photoelectric converters 5a to 5e. Corresponds to the light intensity (electric power) distribution of the light receiving surface of the condenser lens array 14, and the light intensity (electric field) distribution of the light receiving surface of the condenser lens array 14 with respect to the light transmittance distribution of the mask 12. This is because it is a pattern that has been subjected to inverse Freie transform.

The operation of the optically controlled transmission phased array antenna configured as described above will be described below.

A microwave signal frequency-modulated with a baseband signal (hereinafter, this microwave signal is represented by cosωrt for convenience) is input from the transmission device 1 to the distributor 2, and after being distributed by the distributor 2 to 5, The distributed microwave signals correspond to amplifiers 3a to 3e, optically controlled phase shifters 4a to 4e, and optical fiber cables 19a to 19 respectively.
e, the photoelectric converters 5a to 5e, and the power amplifiers 6a to 6e to be output to and radiated to the antennas 7a to 7e.

On the other hand, the optical signal represented by cosωct is transmitted from the semiconductor laser diode 11 to the mask 12, the collimator lens 13,
The light control type phase shifter 4 via the condensing lens array 14 and the polarization maintaining optical fiber cables 15a to 15e.
Each of the input terminals a to 4e is incident. The optical signals incident on the input ends of the optical control type phase shifters 4a to 4e are incident on the branch optical waveguide 21 via the optical waveguide 61, and then are split into two. The optical signal is input to the optical frequency shifter 25 via the optical phase shifter 24 for correcting the amount of phase shift and the optical waveguide 65 via the waveguide 64, and the other distributed optical signal is optically phase-shifted via the optical waveguide 62. Bowl 22
Incident on.

In the optical frequency shifter 25, the frequency ω of the optical signal
After c is shifted by the frequency ωc of the microwave signal input from the amplifiers 3a to 3e, the frequency-shifted optical signal cos (ωc + ωr) t is transmitted through the optical waveguide 66 to the combined optical waveguide 23. It is incident on the first input end. Further, the other distributed optical signal is incident on the optical phase shifter 22 through the optical waveguide 62, and after being phase-shifted by the phase shift amount θ corresponding to the DC voltage applied from the variable voltage source 17, The phase-shifted optical signal cos (ωc + θ) is incident on the second input end of the multiplexing optical waveguide 23 via the optical waveguide 63.

The multiplexing optical waveguide 23 multiplexes the optical signals incident on the first and second input ends, and then multiplexes the multiplexed optical signal cos (ωc
t + θ) + cos (ωc + ωr) t is the photoelectric converter 5 via the optical waveguide 67, the output end 68 of the optically controlled phase shifters 4a to 4e, and the optical fiber cables 19a to 19e.
It is incident on a to 5e. Photoelectric converters 5a to 5e
Is the optical signal cos (ωct + θ) + cos (ω
Each of the microwave signals cos (ωrt−) obtained by square-law detection of c + ωr) t and removal of the direct current component
θ) through the power amplifiers 6a to 6e to the antenna 7
Output to a to 7e. As a result, each microwave signal is radiated from the antennas 7a to 7e.

In the above-mentioned optically controlled phased array antenna, when the operator inputs the beam direction information of the phased array antenna into the input device 80, the information is output to the direction control device 18, and in response thereto, the direction control device. 18
The antenna 7a based on the information on the beam direction.
To 7e so that the beam directions of the microwave signals radiated from the microwave signals are the same as the input beam directions, the predetermined DC voltage is applied from the variable voltage source 17 to the optical phase shifters of the light control type phase shifters 4a to 4e. Output to the electrodes of the container 22. As a result, the phase shift amount θ is phase-shifted, and the microwave signals can be emitted from the antennas 7a to 7e in the desired beam direction input by the operator as described above. Further, since the signal amplitude can be weighted by changing the light transmittance distribution of the mask 12, as in the conventional example, the antenna radiation pattern in the far field can be changed. Therefore, with the configuration shown in FIG. 1, it is possible to change the radiation pattern and scan the beam in the optically controlled phased array antenna.

As described above, the phased array antenna of the present embodiment does not have the configuration of the Mach-Zehnder interferometer as in the conventional example, so that it is not necessary to align the optical axes, and the influence of vibration It is hard to receive. Further, the optical control signal generator 10 can be made smaller and lighter than the optical interferometer in the housing 30 in the conventional example, so that the optical control signal generator 10 can be made significantly larger than the conventional example. Can be made smaller and lighter.

Further, in this embodiment, the light control type phase shifters 4a to 4a are used.
Since the phase shift is performed by applying an electric field to the light traveling in the optical waveguide using the optical phase shifter 22 in e, the mask 37 is directed in the direction perpendicular to the optical axis as in the conventional example. The phase shift can be performed with high accuracy as compared with the shift device, and thus, there is an advantage that desired beam scanning can be performed with high accuracy.

Further, since the optical frequency shifter 25 is composed of a plurality of optical phase shifters as described above, the frequency of incident light is set to It has the advantage that it can be shifted at higher frequencies, such as the waveband, which allows the optically controlled transmission phased array antenna to be used in the frequency band above the microwave band.

Therefore, the optically controlled transmission phased array antenna of the present embodiment is smaller and lighter in weight than the conventional example and is less susceptible to the influence of vibration. Therefore, it can be used as a phased array antenna mounted on a mobile body or a satellite. it can.

In the first embodiment described above, the semiconductor laser diode 11 is used as the light source that outputs coherent light, but the present invention is not limited to this, and a gaz laser may be used.

In the first embodiment described above, the mask 12 has the transmittances of 1 and 0, but the present invention is not limited to this, and the transmittance distribution corresponding to the radiation pattern on the plate surface of the glass plate having the transmittance of 1 is obtained. According to the above, a black light blocking material made of chrome may be applied in a shaded manner. Further, a black plate made of, for example, an epoxy resin, in which holes having a shape corresponding to the radiation pattern are formed, may be used as the mask 12.

In the first embodiment described above, the collimator lens 13 is provided to shorten the optical path length between the mask 12 and the condenser lens array 14, but the invention is not limited to this, and the collimator lens 13 is not provided. May be. At this time, when the light output from the mask 12 reaches the condenser lens array 14, it is necessary to arrange the mask 12 and the condenser lens array 14 so that the pattern distribution of the light is subjected to inverse Fourier transform. is there.

In the first embodiment described above, the condenser lens array 14 is used.
When the light receiving area of each condenser lens is sufficiently small, the parallel light output from the collimator lens 13 may be directly incident on the input ends of the optical fiber cables 15a to 15e.

In the above first embodiment, the case where the five antennas 7a to 7e are arranged side by side in a row has been described. However, the present invention is not limited to this, and a plurality of antennas may be arranged side by side in a row or matrix. . In this case, amplifiers 3a to 3e, optically controlled phase shifters 4a to 4e, photoelectric converters 5a to 5e, power amplifiers 6a to 6e, and optical fiber cables 15a to 1 depending on the number of antennas.
It is necessary to provide each of 5e and 19a to 19e.

Second Embodiment FIG. 3 is a block diagram of an optically controlled reception phased array antenna according to a second embodiment of the present invention. In FIG. 3, the same parts as those in FIG. is doing.

The optically controlled reception phased array antenna of the second embodiment differs from the optically controlled transmission phased array antenna of the first embodiment in the following configuration. That is, the microwave signals received by the antennas 50a to 50e are respectively transmitted to the low noise amplifiers 51a to 51e.
Each of the optical signals input to each of the optical control type phase shifters 4a to 4e via e and output from each of the optical control type phase shifters 4a to 4e is optically multiplexed via optical fiber cables 19a and 19e. After being incident on the multiplexer 52 and multiplexed, the combined optical signal is incident on the photoelectric converter 52 and detected, and the microwave signal obtained by the detection is received by the receiving device 55 via the amplifier 54. Entered in. The reception device 55 performs frequency demodulation processing on the input microwave signal, and then outputs the baseband signal obtained by the processing.

In the above-mentioned optically controlled reception phased array antenna configured as described above, when the operator inputs the beam direction information of the phased array antenna into the input device 80, the information is output to the direction control device 18, and In response to the beam direction information, the direction control device 18 controls each of the predetermined directions so that the beam direction of the microwave signal received by the antennas 50a to 50e becomes the input beam direction. DC voltage is the variable voltage source 1
7 to each of the optical phase shifters 22 of the optical control type phase shifters 4a to 4e
Output to the electrode. As a result, the phase shift amount θ is phase-shifted, and the microwave signals can be received by the antennas 50a to 50e in the desired beam direction input by the operator as described above. Further, since the signal amplitude can be weighted by changing the light transmittance distribution of the mask 12 as in the conventional example, the antenna reception pattern in the far field can be changed. Therefore, with the configuration shown in FIG. 3, it is possible to change the radiation pattern and scan the beam in the optically controlled reception phased array antenna.

The optical control type reception phased array antenna configured as described above has the same effect as that of the first embodiment of FIG. 1 described above.

In the second embodiment described above, the optical signals output from the optically controlled phase shifters 4a to 4e via the optical fiber cables 19a and 19e are combined by the optical combiner 52, and then the photoelectric converter is provided. Although photoelectric conversion is carried out at 53, the present invention is not limited to this, and as shown in FIG.
Each optical signal output from e via the optical fiber cable 19a or 19e may be photoelectrically converted by the photoelectric converters 53a to 53e and then combined by the combiner 56.

As described in detail above, according to the present invention, a plurality of transmission signals or a plurality of antennas are respectively provided for a plurality of optical signals distributed in a pattern corresponding to a predetermined radiation pattern of a phased array antenna. In addition to frequency-shifting only the frequencies of the multiple received signals received by, each phase signal is phase-shifted by the amount corresponding to the beam direction of the input phased array antenna. Optical control that can control the beam direction by changing the amount of each phase shift by radiating from the antenna or multiplexing the optical signals that are phase-shifted and photoelectrically converting to obtain the received signal. Type transmitting phased array antenna or optically controlled receiving phased array antenna can be realized. Therefore, since the phased array antenna of the present invention does not include the Mach-Zehnder interferometer as in the conventional example, it is not necessary to align the optical axis, which makes it less susceptible to vibrations, and There is an advantage that it can be made smaller and lighter than the example.

Further, in the present invention, since the optical phase shift means for shifting each optical signal by a predetermined amount of phase shift is used, the phase shift can be performed with higher accuracy as compared with the conventional example. Thus, there is an advantage that desired beam scanning can be performed with high accuracy.

Furthermore, since the above-mentioned optical phase shifting means for frequency-shifting each optical signal is used, the frequency of the incident light is compared with the conventional example in which the optical signal is composed of an acousto-optic device as in the conventional example. It is possible to shift higher frequencies such as wave bands, which has the advantage that the optically controlled phased array antenna can be used in frequency bands above the microwave band.

Therefore, the optically controlled transmission phased array antenna and the optically controlled reception phased array antenna of the present invention are smaller and lighter in weight than conventional examples and are less susceptible to vibrations, so that they can be mounted on a mobile unit or a satellite. It can be used as a phased array antenna.

[Brief description of drawings]

1 is a block diagram of an optically controlled transmission phased array antenna which is a first embodiment of the present invention, FIG. 2 is a block diagram of the optical frequency shifter of FIG. 1, and FIG. 3 is a second diagram of the present invention. FIG. 4 is a block diagram of an optical control type reception phased array antenna which is an embodiment, FIG. 4 is a block diagram of a transmission phased array antenna of a conventional example, and FIG. 5 is the phased array antenna of FIG. 1, FIG. 2 and FIG. FIG. 6 is a diagram showing the relationship between the light transmittance distribution of the mask and the radiation pattern of the antenna in the far field, and FIG. 6 is a block diagram of an optically controlled reception phased array antenna which is a modification of the second embodiment. 1 ... Transmitter, 2 ... Distributor, 3a to 3e ... Amplifier, 4a to 4e ... Optically controlled phase shifter, 5a to 5e, 53 ... Photoelectric converter, 6a to 6e ... Power amplifier, 7a to 7e, 50a to 50e ... Antenna, 10 ... Optical control signal generator, 11 ... Laser diode, 12 ... Mask, 13 ... Collimating lens, 14 ... Condensing lens array, 15a to 15e, 19a to 19e ... Optical fiber cable, 16, 17 ... Variable voltage source, 18 ... Control device, 20 ... Dielectric substrate, 21 ... Branch optical waveguide, 22, 24 ... Optical phase shifter, 23 ... … Multiplexing optical waveguide, 25 …… Optical frequency shifter, 51 …… Low noise amplifier, 54 …… Amplifier, 55 …… Receiver.

Front Page Continuation (72) Inventor, Koji Yasukawa, Kyoto, Soraku-gun, Seika-cho, Osamu Osamu, Osamu, Mihiratani No.5

Claims (2)

[Claims] 1. A transmission phased array antenna comprising a plurality of antennas (7a-7e), wherein optical signal generating means (1) for generating coherent optical signals.
1) and the optical signal output from the optical signal generating means (11),
First distribution means (12, 13) for distributing a plurality of optical signals each having a light intensity corresponding to a predetermined far-field radiation pattern of the transmission phased array antenna, and transmission signal output means (for outputting a transmission signal ( 1), a second distribution means (2) for distributing the transmission signal output from the transmission signal output means (1) into a plurality of transmission signals, and an output from the first distribution means (12, 13). A plurality of optical signals output from the first distribution means (12, 13) are divided into a pair of a first optical signal and a second optical signal. A plurality of third distribution means (4a) for distributing the first optical signal and the plurality of second optical signals.
-4e 21) and a plurality of first optical signals output from the plurality of third distribution units (4a-4e 21), a plurality of first optical signals output from the second distribution unit (2). A plurality of optical frequency shifter means (4a) for frequency-shifting only the frequency of the transmission signal.
-4e 25) and a plurality of second optical signals output from the plurality of third distribution units (4a-4e 21) corresponding to the beam directions of the transmission phased array antennas that are input. A plurality of optical phase shifting means (4a-4) for respectively shifting the phase by the phase shift amount.
e), the plurality of first optical signals output from the plurality of optical frequency shifter means (25 of 4a-4e), and the plurality of optical phase shifting means (22 of 4a-4e). The plurality of second optical signals are output from the plurality of combining means (23 of 4a-4e) for combining each corresponding pair and the plurality of combining means (23 of 4a-4e). A plurality of photoelectric conversion means (5a-5e) for detecting a plurality of optical signals and outputting a transmission signal to the plurality of antennas (7a-7e), respectively. 5e)
A plurality of transmission signals output from the antenna (7a-
Optically controlled transmission phased array antennas characterized in that they are radiated respectively from 7e). 2. A plurality of antennas (50) for receiving a received signal.
a-50e) in the reception phased array antenna, the optical signal generating means (1) for generating a coherent optical signal.
1) and the optical signal output from the optical signal generating means (11),
First distributing means (12, 13) for distributing to a plurality of optical signals each having a light intensity corresponding to a predetermined far field reception pattern of the reception phased array antenna; and the first distribution means (12, 13). ), Each optical signal output from the first distributing means (12, 13) is divided into a pair of a first optical signal and a second optical signal. As described above, a plurality of fourth distribution means (4a) for distributing the plurality of first optical signals and the plurality of second optical signals.
-4e 21) and a plurality of first optical signals output from the plurality of fourth distributing units (21a of 4a-4e), and a plurality of first optical signals output from the plurality of antennas (50a-50e). A plurality of optical frequency shifter means (25 of 4a-4e) for shifting the frequency of the transmission signal respectively, and a plurality of second light outputted from the plurality of fourth distributing means (21 of 4a-4e). A plurality of optical phase shift means (4a-4) for shifting the signal by the respective phase shift amounts corresponding to the beam directions of the input reception phased array antenna.
e), the plurality of first optical signals output from the plurality of optical frequency shifter means (25 of 4a-4e), and the plurality of optical phase shifting means (22 of 4a-4e). A plurality of first multiplexing means (23 of 4a-4e) for respectively multiplexing the plurality of second optical signals corresponding to each pair, and the plurality of first multiplexing means (4a-4e). No. 23), a second combining means (5) for combining a plurality of optical signals outputted from
2) and a photoelectric control means (53) for detecting an optical signal output from the second multiplexing means (52) and outputting a reception signal, the optical control type reception phased array antenna. .