JPH05235606A - Microwave circuit - Google Patents

Abstract

PURPOSE:To obtain the microwave circuit in which a control signal is easily applied to control elements even when number of the control elements is high. CONSTITUTION:Light control element switches 70a, 70c pass a signal wave when a light whose wavelength is lambda1, irradiates to the switches and light control element switches 70b, 70d pass the signal wave when a light whose wavelength is lambda2, irradiates to the switches, and the difference of the length between microstrip lines 3a and 3b is set L in the microwave circuit (phase shifter). A phase of the output signal wave with respect to a same input signal wave is changed by an electric length of the line length difference L with the case that the light whose wavelength is lambda1, is emitted but the light whose wavelength is lambda2 is not emitted, as the control signal and the case that the light whose wavelength is lambda1, is not emitted but the light whose wavelength is lambda2, is emitted as the control signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave or millimeter wave band radio wave transmission circuit for controlling its transmission characteristics by irradiating light.

[0002]

2. Description of the Related Art FIG. 14 is a block diagram showing a digital phase shifter of a microwave circuit provided with a conventional control element shown in C-49 of the 1991 Spring National Conference of the Institute of Electronics, Information and Communication Engineers. In the figure, 1 is a dielectric substrate having a ground conductor on one surface, 3a to 3c are strip conductors of a microstrip line, 4 is an input terminal, 5 is an output terminal, 7 is a through hole, 8 is a control signal line, and 9a. Reference numerals 9b and 9b are control signal input terminals, and 16a to 16c are field effect transistors (hereinafter referred to as FETs). 15 is an equivalent circuit diagram of the microwave circuit shown in FIG. 15, 70a to 70c are switches equivalently representing the FETs 16a to 16c of FIG. 14, and 71a to 71c are electrical lengths λ / 4 (λ: wavelength of a signal wave) equivalently representing the strip conductors 3a to 3c. The transmission lines 72a and 72b are equivalent to the grounding through the through holes. Switches 70a-7
0c is in the connected state when the control signal is input, and is in the disconnected state when the control signal is not input.

Next, the operation of the microwave circuit is shown in FIG.
This will be described with reference to FIGS. In FIG. 16, when the control signal is input to the control signal input terminal 9a and the control signal is not input to the control signal input terminal 9b, that is, the switches 70a and 70
FIG. 5B is an equivalent circuit diagram showing a case where the connection state b and the switch 70c are in the disconnection state. In FIG. 16, the signal wave input to the input terminal 4 is output to the output terminal 5 via the transmission line 71b having a length of λ / 4 with a phase delay of 90 degrees. Here, since the transmission lines 71a and 71c are transmission lines having a length λ / 4 with one end grounded, the transmission lines 71a and 71c viewed from the connection point with the transmission line 71b at the other end can be regarded as open. ..

On the other hand, in FIG. 17, when the control signal is not input to the control signal input terminal 9a and the control signal is input to the control signal input terminal 9b, that is, the switches 70a and 70b are cut off.
The switch 70c is an equivalent circuit diagram showing a case where the switch 70c is in a connected state. In FIG. 17, the signal wave input to the input terminal 4 is transmitted through the transmission lines 71a and 71c having a length of λ / 4 to 18
It is output to the output terminal 5 with a phase delay of 0 degree. Here, since the transmission line 71b is a transmission line having a length λ / 4 with one end grounded, the transmission line 71b viewed from the connection point of the transmission lines 71b and 71c at the other end can be regarded as an open line.

As described above, when the control signal is input to the control signal input terminal 9a and is not input to the control signal input terminal 9b, and when the control signal is not input to the control signal input terminal 9a,
Since the length of the transmission line through which the signal wave passes differs from that when input to the control signal input terminal 9b by λ / 4, the phase can be changed by 90 degrees.

[0006]

Since the conventional microwave circuit having the control element is constructed as described above,
In the case of a microwave circuit having a large number of control elements, a large number of control signal lines are required, which poses a problem in that there are restrictions in terms of circuit layout and miniaturization.

The present invention has been made to solve the above problems, and an object thereof is to obtain a microwave circuit which can easily supply a control signal and can be miniaturized even when the number of control elements is large. ..

[0008]

In order to achieve the above object, a microwave circuit according to the present invention comprises a plurality of light control elements for controlling microwave transmission characteristics by irradiating light. Of the above light control elements, at least two elements have different wavelength characteristics of light receiving sensitivity.

[0009]

In the microwave circuit according to the present invention configured as described above, the control signal line on the microwave circuit can be eliminated by using a plurality of lights having different wavelengths as the control signal.

[0010]

EXAMPLES Example 1. 1 is a configuration diagram showing a first embodiment of a microwave circuit according to the present invention. FIG. 2 is a diagram for explaining the relationship between the microwave circuit 80 and the control signal light source 6 shown in FIG. FIG. 3 is an equivalent circuit diagram of FIG. FIG. 4 is a configuration diagram showing an optical control element of the microwave circuit shown in FIG. In the figure, 1 is a dielectric substrate having a ground conductor on one surface,
3 is a strip conductor of a microstrip line, 4 is an input terminal, 5 is an output terminal, 6 is a control signal light source capable of outputting any one of a plurality of lights having different wavelengths, or a plurality of lights at the same time, 10a and 10b are light control elements, Reference numeral 80 denotes the entire microwave circuit.

Next, the operation will be described. As shown in the equivalent circuit diagram of FIG. 3, the switches 70a and 70c have wavelengths λ ₁
The signal waves are passed by the irradiation of the light of the switch 70b, 7
0d is configured to pass a signal wave by irradiation with light of wavelength λ ₂ .

First, when the light of the wavelength λ ₁ is irradiated and the light of the wavelength λ ₂ is not irradiated, the switches 70a and 70c pass the signal wave, and the switches 70b and 70d are turned off.
The signal wave input to the input terminal 4 passes through the switch 70a, the microstrip line 3a and the switch 70c and is output from the output terminal 5.

Next, when the light of the wavelength λ ₂ is irradiated without irradiating the light of the wavelength λ ₁ , the switches 70a and 70c block the signal wave and the switches 70b and 70d pass the signal wave.
The signal wave input to the input terminal 4 passes through the switch 70b, the microstrip line 3b and the switch 70d and is output from the output terminal 5.

Here, the microstrip lines 3a and 3
When b of the difference in length is L, and when not irradiated with light of wavelength lambda ₂ by irradiating light of wavelength lambda ₁ as the control signal, the wavelength lambda ₂
When the light having the wavelength λ ₁ is not emitted and the light having the wavelength λ ₁ is emitted, the phase of the output signal wave with respect to the same input signal wave can be changed by the electrical length of the line difference L.

Although a single-bit phase shifter has been described as an example here, a multi-bit phase shifter is formed by connecting in series a plurality of switches having different wavelength characteristics of photosensitivity and elements having different phase shift amounts. Can be realized.

FIG. 4 is a block diagram showing an optical control element of the microwave circuit shown in FIG. In the figure, 1 is a dielectric substrate having a ground conductor on one surface, 3 is a strip conductor of a microstrip line, and 81 is a semiconductor film whose conductivity changes by irradiation with light of a specific wavelength. When not illuminated
Since the semiconductor film 81 is in a non-conducting state, the switch is in a cutoff state. On the other hand, when the semiconductor film 81 is irradiated with light, the semiconductor film 81 is in a conductive state, so that the switch is in a connected state. The wavelength selectivity is changed by changing the type of the semiconductor film 81 of the switches 70a and 70b.

Embodiment 2. In Example 1, as an optical control element (switch) of the microwave circuit (phase shifter) of FIG.
As shown in (4), the type of the semiconductor film 81 whose conductivity changes by irradiation with light of a specific wavelength is changed to provide photoselectivity.
The same kind of semiconductor film 81 is provided, and the same effect is obtained by disposing a film passing only a specific wavelength on the semiconductor film. FIG. 5 is a configuration diagram showing a second embodiment of the light control element (switch) of the microwave circuit according to the present invention. In the figure, 81a is a semiconductor film whose conductivity changes by irradiation with light, and 82 is a film which passes only light of a specific wavelength. Membrane 8
When the light passing through 2 is irradiated, the semiconductor film 81a becomes conductive and the switch becomes in the passing state. On the other hand, the membrane 82
The semiconductor film 81a is in a non-conductive state and the switch is in a cutoff state when the light which does not pass through the light is irradiated and when the light is not irradiated.

Example 3. In the first embodiment, the microwave circuit including a single phase shifter or a plurality of phase shifters has been described. Further, an example of the microwave circuit configured on the same substrate in combination with the microwave circuit such as the antenna and the mixer is described. explain. 6 and 7 are configuration diagrams showing a third embodiment of the microwave circuit according to the present invention. 6 is a configuration diagram showing the light control element mounting surface of Example 3, and FIG. 7 is a diagram showing the back surface of FIG. 6 and 7, 1A is a dielectric substrate, 2 is a ground conductor, 3 is a strip conductor of a microstrip line, 5 is an output terminal, 7 is a through hole,
11 is a radiation conductor of the microstrip antenna, 80a
80h is the microwave circuit (phase shifter) 80 shown in FIG.
Is the same as.

Next, the operation will be described focusing on the microwave circuit (phase shifter) 80a. The signal wave incident on the radiation conductor 11 of the microstrip antenna of FIG. 7 is input to the light control microwave circuit 80a via the through hole 7 and the microstrip line including the strip conductor 3 and the ground conductor 2. Microwave circuit (phase shifter) 80a
In, the signal wave having a predetermined phase change is output to the output terminal 5 via the microstrip line including the strip conductor 3 and the ground conductor 2.

Here, if the wavelength characteristics of the light receiving sensitivity of the light control elements of the microwave circuits 80a to 80h are changed, the microwave circuits 80a to 80h are independently set according to the wavelength of the light emitted by the control signal light source 6. Can be controlled. Therefore, the beam direction of the antenna composed of the radiating conductors 11 can be changed to a predetermined direction by the control signal light source 6.

Example 4. 8 and 9 are configuration diagrams showing a fourth embodiment of the microwave circuit according to the present invention. The same parts as those in FIGS. 6 and 7 showing the third embodiment are designated by the same reference numerals and the description thereof is omitted because they have already been described. FIG. 8 is a configuration diagram showing the light control element mounting surface of the fourth embodiment. FIG. 9 is a view showing the back surface of FIG. 8 and 9, 6 is a control signal light source capable of outputting any one of a plurality of lights having different wavelengths or a plurality of lights at the same time, and 91 is a light source for generating light modulated by a local oscillation signal. 80 is a microwave circuit (phase shifter) controlled by the same control signal light source 6 as shown in FIG.
Reference numeral 0 is a mixer circuit to which a local oscillation signal is supplied by the modulated light.

Next, the operation will be described. The signal wave incident on the radiation conductor 11 of the microstrip antenna of FIG. 9 is input to the microwave circuit (phase shifter) 80 via the through hole 7 and the microstrip line including the strip conductor 3 and the ground conductor 2, Each phase is adjusted.
Next, the mixer circuit 90 mixes with the local oscillation signal supplied by the irradiation of the light source 91 which is modulated by the local oscillation signal to generate an intermediate frequency signal. Mixer circuit 90
The intermediate frequency signal generated in 1 is output to the output terminal 5 via the microstrip line including the strip conductor 3 and the ground conductor 2.

Example 5. In the first embodiment, a microwave circuit (phase shifter) 80 configured by using a microstrip line
The optical control element (switch) of the above has been described, but the optical control element (switch) of the microwave circuit configured by using the coplanar line and the slot line will be described. Figure 10
Is an optical control element (switch) of the microwave circuit of the present invention
It is a block diagram which shows Example 5 of. In the figure, 1A is a dielectric substrate, 2 is a ground conductor, 20 is a center conductor of a coplanar line, and 81a is a semiconductor film whose conductivity changes by irradiation with light of a specific wavelength. Now, when the semiconductor film 81a is irradiated with light of a specific wavelength and the semiconductor film 81a is in a conductive state, the center conductor 20 of the coplanar line is grounded, and the signal wave propagating through the coplanar line is totally reflected. On the other hand, when the semiconductor film 81a is brought into a non-conducting state without being irradiated with light of a specific wavelength, the coplanar line can pass a signal wave.

Example 6. 11 is a configuration diagram showing a sixth embodiment of an optical control element (phase shifter) of a microwave circuit according to the present invention. In FIG. 11, reference numeral 2 is a ground conductor, 20 is a central conductor of a coplanar line, 81b is a light control element formed of a semiconductor element whose permittivity changes by irradiation of light, and 83 is a semi-insulating G layer.
It is an aAs substrate. When the light control element is irradiated with light, plasma is generated in the semiconductor element 81b of the light control element, and the dielectric constant of the semiconductor element 81b changes. When the permittivity changes, the wavelength shortening rate of the coplanar line changes,
The passing phase can be changed.

Example 7. 12 and 13 are configuration diagrams showing a seventh embodiment of the microwave circuit (multi-bit phase shifter) of the present invention. A multi-bit phase shifter can be configured by connecting in series a plurality of light control elements (single-bit phase shifters) whose amount of phase shift can be changed according to the wavelength of the irradiation light shown in FIG. .. FIG. 12 is a configuration diagram (plan view) showing a seventh embodiment of the multi-bit phase shifter. FIG. 13 shows FIG.
2 is a sectional view taken along line AA ′ of FIG. In FIGS. 12 and 13, 2
Is a ground conductor, 20 is a center conductor of a coplanar line, 81b,
Reference numerals 81c and 81d are the same as those of the light control element shown in FIG. 11, respectively, and semiconductor elements whose permittivity is changed by irradiation of light, and 83 are semi-insulating GaAs substrates. Three types of semiconductor elements 81b, 81 whose permittivity changes with light of different wavelengths
The amount of phase shift can be changed by using c and 81d for one coplanar line and changing the length of each semiconductor element. This makes it possible to realize a 3-bit phase shifter.

Example 8. In the microwave circuits shown in Examples 1, 2, 3, 4, and 5, the dielectric substrate 1 may be a semiconductor substrate, that is, a monolithic structure, in order to suppress variations in the light control elements. Has the same effect.

[0027]

As described above, according to the present invention, among the optical control elements for controlling the transmission characteristics of microwaves by irradiating light, at least two elements have different wavelength characteristics of the light receiving sensitivity so that the wavelengths are different. By using a plurality of lights as the control signal, it is possible to obtain a small microwave circuit that can easily supply the control signal even when the number of control elements is large.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a microwave circuit according to the present invention.

FIG. 2 is a diagram illustrating a relationship between the microwave circuit shown in FIG. 1 and a control signal light source.

FIG. 3 is an equivalent circuit diagram of FIG.

4 is a configuration diagram showing an optical control element (switch) of the microwave circuit shown in FIG.

FIG. 5 is a configuration diagram showing a second embodiment of an optical control element (switch) of the microwave circuit of the present invention.

FIG. 6 is a configuration diagram (light control element mounting surface) showing a third embodiment of the microwave circuit according to the present invention.

FIG. 7 is a diagram showing the back surface of FIG.

FIG. 8 is a configuration diagram (light control element mounting surface side) showing a fourth embodiment of the microwave circuit of the present invention.

9 is a diagram showing the back surface of FIG.

FIG. 10 is a configuration diagram showing a fifth embodiment of an optical control element (switch) of a microwave circuit according to the present invention.

FIG. 11 is a configuration diagram showing a sixth embodiment of an optical control element (phase shifter) of a microwave circuit according to the present invention.

FIG. 12 is a configuration diagram showing a seventh embodiment of an optical control element (phase shifter) of a microwave circuit according to the present invention.

13 is a cross-sectional view taken along the line AA ′ in FIG.

FIG. 14 is a configuration diagram showing a conventional microwave circuit.

FIG. 15 is an equivalent circuit diagram of FIG.

16 is an equivalent circuit diagram for explaining the operation of FIG.

FIG. 17 is an equivalent circuit diagram illustrating the operation of FIG.

[Explanation of symbols]

 1 Dielectric Substrate 2 Ground Conductor 3 Microstrip Line Strip Conductor 3a to 3c Microstrip Line Strip Conductor 4 Input Terminal 5 Output Terminal 6 Control Signal Light Source 7 Through Hole 10a to 10b Light Control Element 11 Radiation Conductor 20 Coplanar Line Center Conductors 70a to 70d Switch 80 Microwave circuit having light control element 80a to 80h Microwave circuit having light control element 81 Semiconductor film 81a, 81b, 81c, 81d Semiconductor film 82 Film that transmits light of specific wavelength 83 Semi-insulating property GaAs substrate 90 Mixer circuit 91 Light source for generating light modulated by local signal

Front page continuation (72) Inventor Shuji Urasaki 5-1, 1-1 Ofuna, Kamakura-shi Electronic Systems Research Center, Mitsubishi Electric Corporation

Claims (1)

[Claims] 1. A microwave circuit comprising a plurality of light control elements for controlling microwave transmission characteristics by irradiating light, wherein at least two of the light control elements have different light receiving sensitivity wavelength characteristics. A microwave circuit characterized in that.