JP2000286651A - Multichannel high-frequency signal supplying device and high-frequency switch device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a multichannel high-frequency signal supplying device the switching ability of which does not deteriorate even when a large-output signal source is used and a high-frequency switch device. SOLUTION: To each branch line L (L1 and L2) which leads high-frequency signals generated from an oscillator 4 and branched by means of a branching circuit 6 to output ports P1 and P2, switch amplifiers 8 (8a and 8b) which conduct and disconnect the lines L and limit amplifiers 10 (10a and 10b) which limit the upper-limit power of the inputs to the amplifiers 8 are respectively connected. The saturated output power Pmax of the limit amplifiers 10 is set in such a way that the power Pmax becomes equal to or smaller than the gain compressing power P which is the input power when the small-signal gains of the switch amplifiers 8 drop by 1 dB or smaller (P>=Pmax). Therefore, even when the power supply to the lines L is large, the ratio between the output signal intensities at the conducting time and disconnecting time is not deteriorated, because the switch amplifiers 8 only operate in linear areas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various devices utilizing high frequency signals in a millimeter wave band or a microwave band, and more particularly to a multi-channel high frequency signal supply device and a high frequency switching device used for a transceiver.

[0002]

2. Description of the Related Art Conventionally, as a high-frequency switch used in a transmission line of a high-frequency signal, for example, Japanese Patent Application Laid-Open No. 2-63 is disclosed.
As disclosed in JP-A-201-201 and JP-A-5-55804, there is known an apparatus using an amplifier composed of transistors (hereinafter, referred to as a switch amplifier).

[0003] Such a switch amplifier has recently been
For example, application to a transmitter / receiver of an on-vehicle radar device, that is, a multi-channel high-frequency signal supply device that supplies a transmission signal to any of a plurality of transmission antennas arranged so that transmission beams are directed to different regions, In order to simplify the configuration of the receiver, it has been considered that a mixer is shared by a plurality of receiving antennas and is used for a selector or the like that supplies only a signal received from any one of the receiving antennas to the mixer.

[0004]

When a transmission signal is supplied to a plurality of transmission antennas by the above-described multi-channel high-frequency signal supply device, the transmission signal generation source includes:
A high-output oscillator using a Gunn diode or the like is used. However, when a large transmission signal generated by such an oscillator is input to the above-described switch amplifier, the switching performance of the switch amplifier deteriorates. There was a problem.

That is, the switching performance of a switch amplifier is evaluated based on the difference (on / off ratio) of the signal strength appearing at the output between a conduction state and a cutoff state.
Determined based on the signal transmittance when the transistor is off,
The signal transmittance is constant regardless of the magnitude of the input power. Therefore, in the region where the output changes linearly with respect to the input of the switch amplifier, the signal strength at the time of conduction and at the time of cutoff increases at the same rate as the input power increases. However, in the region where the output of the switch amplifier is saturated, the signal strength at the time of conduction becomes almost constant regardless of the magnitude of the input power, and only the signal strength at the time of cutoff increases according to the input power. The larger the value, the more the on / off ratio deteriorates, and the performance as a switch deteriorates.

[0006] Further, this type of device has a M
In many cases, the MIC is used, but in the MMIC, such a problem is likely to occur because the range of usable power is further limited. An object of the present invention is to provide a multi-channel high-frequency signal supply device and a high-frequency switching device that can reliably prevent a decrease in switch performance even when a high-output signal source is used, in order to solve the above-described problems. And

[0007]

According to a first aspect of the present invention, there is provided a multi-channel high-frequency signal supply apparatus comprising: an oscillator configured with a Gunn diode for generating a high-frequency signal; The branch circuit supplies the high-frequency signal to each of the branch lines reaching the plurality of output ports. Each branch line is turned on and off by switching means that operates in response to an external control signal, and a high-frequency signal is supplied through an output port of the turned-on branch line.

In the present invention, the switching means comprises:
The limiting means limits the upper limit power of the high-frequency signal supplied from the distribution circuit to the branch line, and the switch amplifier converts the high-frequency signal having the limited upper limit power into a control signal. According to the reflection,
Alternatively, conduction and cutoff of the branch line are performed by amplifying and passing.

In the multi-channel high-frequency signal supply apparatus according to the present invention, the upper limit power limited by the limiting means in accordance with the magnitude of the output of the oscillator is set so that the output of the switch amplifier is not saturated. By doing
Deterioration of the on / off ratio can be reliably prevented.

The magnitude of the output of the switch amplifier at which the output is not saturated is, specifically, a gain compression power that is an input power when the small signal gain of the switch amplifier is reduced by 1 dB. The upper limit power may be set to be equal to or less than the gain compression power. That is,
Assuming that the gain compression power of the switch amplifier is P and the upper limit power limited by the limiting means is Pmax, the relationship of P ≧ Pmax may be satisfied.

However, as can be seen from the graph showing the relationship between the input power and the power gain of the amplifier shown in FIG. 8A, the small signal gain is a region where the output signal changes linearly with respect to the input signal. , And the gain compression power P defines an area in which the input and the output can be regarded as having a linear relationship.

Next, in the multi-channel high-frequency signal supply device according to the third aspect, the limit means amplifies the high-frequency signal supplied to the branch line, and sets the limit so that the amplified output is saturated at the upper limit power. Consists of an amplifier. That is,
The characteristic representing the relationship between the input power and the output power of the limit amplifier is set as shown in the graph of FIG.

When such a limit amplifier is used,
Regardless of the power intensity of the input, the output is reliably limited to the upper limit power or less, so there is no need to adjust the limit amplifier according to the power intensity of the high-frequency signal supplied through the branch circuit, and the production of the device Can be simplified.

However, when the limit amplifier is operating in a saturation region where the output is saturated, its output, that is, the input to the switch amplifier, has amplitude distortion in which the amplitude waveform is distorted and phase distortion in which the output phase changes. Will occur. However, it is difficult to form an amplifier for a high frequency such as a millimeter wave or a microwave band in a wide band, and usually, a narrow band amplifier that amplifies only a frequency component near a used frequency is used.
Since it also has a function as a so-called filter, harmonic components generated by distortion of the waveform by the limit amplifier are removed by the switch amplifier. As a result, the output of the switch amplifier is waveform-shaped, and as a result, the entire switching means can supply a high-frequency signal with little distortion.

FIG. 9 shows that the frequency is 76.5 GHz,
It is a graph showing the result of having performed a simulation using three types of input signals whose signal levels were set to -10 dBm, 0 dBm, and +10 dBm and setting the upper limit power limited by the limit amplifier to +5 dBm. The output, (b), is the output of the switch amplifier.
This simulation result shows that the output of the limit amplifier has a larger distortion as the input is larger, and the output of the switch amplifier shows that the distortion generated in the limit amplifier is removed to some extent.

The limit amplifier may be configured to start and stop according to conduction and cutoff of the branch line by the switch amplifier. In this case, the limit amplifier also functions as a switch, and a product obtained by multiplying the ON / OFF ratio of both the limit amplifier and the switch amplifier becomes the ON / OFF ratio of the switching means as a whole, thereby significantly improving the switching performance. be able to.

However, if there is a time lag between the on / off timings of the limit amplifier and the switch amplifier, there is a possibility that inconvenience such as oscillation may occur in some cases.
Therefore, it is preferable that both the switch amplifier and the limit amplifier are configured using transistors having the same characteristics.

That is, at a high frequency, a slight variation in the characteristics of the transistor greatly affects the switching time. Therefore, it is easier to use a transistor of the same design and the same characteristic to obtain a uniform response to a control signal. It is. In an amplifier using a transistor, for example, when the source terminal of the transistor is grounded,
By controlling the bias voltage to the drain terminal, the switching operation can be performed.If the transistors having the same characteristics are used for the limit amplifier and the switch amplifier, the drain terminals of both amplifiers can be shared,
Bias supply control can also be simplified.

Further, as described in claim 6, the switch amplifier and the limit amplifier may be configured using not only transistors but also input matching circuits having the same characteristics.
That is, since the characteristics of the switch amplifier and the limit amplifier configured using the transistors can be set by the output matching circuit, the other configurations can be shared.

In this case, variations in the characteristics of the switches of the two amplifiers can be reduced, and the circuit configuration is shared, so that the design of the device can be simplified.
By the way, in recent years, digital multi-level modulation has been frequently used in radio communication systems using radio waves such as millimeter waves and microwaves, and devices applied to these transceivers have signals that have a large effect on communication quality. Must be minimized.

For this purpose, it is effective to use a variable gain amplifier capable of adjusting a small signal gain by an external gain adjustment signal as the limiting means. That is, as shown in FIG. 10A, when the upper limit PI of the input power to the limiting unit belongs to a region where the output power is saturated (saturation region), the small signal gain of the variable gain amplifier, that is, the input power, By adjusting the slope of the region (linear region) in which the output power changes linearly, the entire range of the input power is set to belong to the linear region as shown in FIG. The input distortion to the input can be reduced.

When the variable gain amplifier is used as the limiting means, the power of the high-frequency signal output via each output port can be made uniform. That is,
For example, as shown in FIG.
Has three branch lines L1 to L3 each reaching the output port P1 to P3, the branch circuit 106 that distributes the power of the high-frequency signal generated by the oscillator 104 from the outer branch line L1, The line length reaching the switching means SW1 and SW3 provided in L3 is the same as that of the branch circuit 1
There is a corner portion C which is longer than the line length from 06 to the switching means SW2 provided on the inner branch line L2, and has a large loss of a high-frequency signal in the outer branch lines L1 and L3. In other words, each of the switching means SW1 to SW3 depends on the line length and line shape of the branch line from the branch circuit 106 to each of the switching means SW1 to SW3.
Therefore, a difference occurs in the input power to the high-frequency signals, and the power of the high-frequency signal output through the output ports P1 to P3 is different from each other. However, if a variable gain amplifier is used as the limiting means constituting the switching means, it is necessary to adjust the small signal gain of the variable gain amplifier according to the difference in loss caused by the line length and line shape of the branch line reaching the switching means. Thus, any of the switching means can make the input power to the switch amplifier uniform, and thus can make the power of the high-frequency signal output through each output port uniform.

The small signal gain of the variable gain amplifier is adjusted, for example, when the variable gain amplifier has a transistor whose source terminal is grounded, as described in claim 8. Alternatively, it can be realized by changing the voltage applied to the gate terminal according to the gain adjustment signal. In particular, when a gain adjustment signal is applied to the gate terminal, a change in power consumption of the transistor when the small signal gain is changed can be reduced.

In the case where the variable gain amplifier includes a pair of cascode-connected transistors, the voltage applied to the gate terminal of the output-side transistor of the pair of transistors may be reduced. The small signal gain may be adjusted by changing according to the gain adjustment signal.

According to a tenth aspect of the present invention, the variable gain amplifier includes a pair of cascode-connected transistors, and a variable resistor which connects an input side and an output side of the pair of transistors to form a negative feedback circuit. Is provided, the small signal gain may be adjusted by changing the resistance of the variable resistor according to the gain adjustment signal.

When a pair of cascode-connected transistors is used, the variable range of the small signal gain can be made as wide as 20 dB or more, and various sizes can be obtained. Can respond to signals. As a variable resistor constituting the negative feedback circuit, for example, a drain terminal and a source terminal are connected to a feedback source and a feedback destination of the negative feedback circuit, and the gain adjustment signal is connected to a gate terminal. Can be used.

According to a twelfth aspect of the present invention, there is provided a multi-channel high-frequency signal supply device, wherein a variable attenuator capable of adjusting an attenuation amount by an external attenuation adjustment signal instead of using a limit amplifier or a variable gain amplifier as limiting means. Is used. In this case, by adjusting the amount of attenuation of the variable attenuator so that the switch amplifier operates in the linear region according to the magnitude of the input power to the switching means, the upper limit is given to the switch amplifier. High-frequency signals with limited power can be supplied without distortion.

The variable attenuator may be, for example,
As described, a stub having one end connected to the branch line,
The other end of the stub may be configured by a transistor that opens and closes the ground, or a stub having one end connected to a branch line, a cathode connected to the other end of the stub, and an anode connected to the other end of the stub. It may be constituted by a grounded diode.

When a transistor is used, the voltage applied to the gate terminal of the transistor is changed, and when a diode is used, the voltage applied to the diode is changed according to the attenuation adjustment signal. Since the end of the stub to which the is connected changes between the open state and the ground state, and according to the state, the passing amount / reflection amount of the specific frequency component resonating in the stub changes,
The output attenuation with respect to the input to the variable attenuator changes.

Next, in the multi-channel high-frequency signal supply device according to a fifteenth aspect, the switching means comprises a second branch circuit, a switch amplifier, and a synthesis circuit, and the second branch circuit includes a high-frequency signal supplied to the branch line. Power distribution,
A plurality of second branch lines are supplied to each of the plurality of second branch lines, and a switch amplifier provided for each of the second branch lines converts a high-frequency signal supplied from the second branch circuit to the second branch line according to a control signal. The signal is reflected or amplified and passed, and further, the combining means combines the outputs of the switch amplifiers provided for the respective second branch lines to obtain the output of the switching means.

That is, in the present invention, the power handled by each switch amplifier is reduced by the plurality of switch amplifiers sharing and blocking the high-frequency signal supplied to one output port in parallel. become. For this reason,
By setting the number of branches according to the output of the oscillator so that the input is reduced to the extent that the output of the switch amplifier is not saturated, it is possible to reliably prevent the on / off ratio of the switching means from being deteriorated.

Further, in the present invention, as in the case of using the limiting means composed of the variable attenuator, the input to the switch amplifier is not distorted. High frequency signals can be supplied. Furthermore, according to the present invention, since the signal is not forcibly saturated or attenuated, the input power is not wasted, and a device with excellent power use efficiency can be configured.

The number of branches of the second branch circuit is, specifically, the high-frequency signal supplied to each of the second branch lines is such that the small signal gain of the switch amplifier is reduced by 1 dB. What is necessary is just to set it to be equal to or less than the gain compression power which is the input power at the time of the execution.

By the way, of the multi-channel high-frequency signal supply device described above, only the configuration of the switching means may be extracted and configured as a high-frequency switching device. That is, a high-frequency switching device according to claim 17 comprises a switching amplifier and a limiting unit, and the limiting unit limits the upper limit power of the high-frequency signal supplied to the transmission line for the high-frequency signal. The limited high-frequency signal is converted by the switch amplifier according to the control signal.
The transmission line is conducted or cut off by reflection or amplification and transmission.

Therefore, according to the high-frequency switching device of the present invention, the upper limit power limited by the limiting means is set to a value that does not saturate the output of the switch amplifier in accordance with the power of the high-frequency signal supplied to the transmission line. By setting so that the ON / OFF ratio of the switch amplifier is reliably prevented from deteriorating, and a signal with small distortion is output during conduction, so that high-quality switching performance can be realized.

Further, the high-frequency switching device of the present invention can be suitably used not only when configuring a transmitting device but also a receiving device of a communication device. It should be noted that any of the items described in claims 2 to 15 can be applied to the high-frequency switching device of the present invention, and similar effects can be obtained.

[0037]

Embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] FIG. 1 is a block diagram showing a transmitter for transmitting a millimeter wave band radar wave which is constituted by using the two-channel high frequency signal supply device of the first embodiment.

As shown in FIG. 1, a two-channel high-frequency signal supply device according to the present embodiment (hereinafter, simply referred to as a signal supply device).
Reference numeral 2 denotes a high-output (+15 dBm to +20 dBm in this embodiment) oscillator 4 for generating a high-frequency signal in a millimeter wave band (76 GHz to 77 GHz band in this embodiment) using a Gunn diode; And a branch circuit 6 for equally dividing the power.

The signal supply device 2 also includes a pair of branch lines L (L1, L1) from the branch circuit 6 to output ports P (P1, P2) to which the transmitting antennas A (A1, A2) are connected.
L2), a switch amplifier 8 (8a, 8b) for conducting and blocking the branch line L, and a limit amplifier 10 (10a, 10b) for limiting the upper limit power of the high-frequency signal input to the switch amplifier 8. And are connected respectively.

Hereinafter, the branch line L1, the switch amplifier 8
a, the limit amplifier 10a and the output port P1 are called a channel CH1, and the branch line L2, the switch amplifier 8b, the limit amplifier 10b and the output port P2 are called a channel CH2. Among them, the switch amplifier 8 is a high electron mobility field effect transistor (HEMT: High Electron Mobility).
Transistor) 20, and the source terminal of HEMT 20 is grounded. The switch amplifier 8
Has a high-frequency line 21 having one end connected to the gate terminal of the HEMT 20 and the other end connected to the input terminal TIS of the switch amplifier 8, and a DC cut capacitor 2 having one end.
7, an input matching circuit 23 including a stub 22 having the other end connected to the input terminal TIS, and one end connected to the HEM.
A high-frequency line 24 connected to the drain terminal of T20 and the other end connected to the output terminal TOS of the switch amplifier 8;
And an output matching circuit 26 comprising a stub 25 having one end grounded via a DC cut capacitor 28 and the other end connected to an output terminal TOS. Stub 2
A control terminal TCS for applying a drain bias voltage as a control signal for controlling ON / OFF of the HEMT 20 is provided between the capacitor 5 and the capacitor 28.

On the other hand, the limit amplifier 10 has the same configuration as that of the switch amplifier 8, and has a source terminal connected to the grounded HEMT 30, one end connected to the gate terminal of the HEMT 30, and the other end connected to the input terminal of the limit amplifier 10. Terminal T
An input matching circuit 33 composed of a high-frequency line 31 connected to IL and a stub 32 having one end grounded via a DC cut capacitor 37 and the other end connected to an input terminal TIL.
And a high-frequency line 34 having one end connected to the drain terminal of the HEMT 30 and the other end connected to the output terminal TOL of the limit amplifier 10, and one end grounded via a DC cut capacitor 38, and the other end connected to the output. An output matching circuit 36 comprising a stub 35 connected to the terminal TOL; and a HEMT between the stub 35 and the capacitor 38.
A control terminal TCL for applying a drain bias voltage is provided as a control signal for controlling ON / OFF of the switch 30.

The output terminal TOL of the limit amplifier 10 is connected to the input terminal T
IS, is connected to the input terminal TIL of the limit amplifier 10 so that the high-frequency signal power-divided by the branch circuit 6 is applied to the input terminal TIL of the limit amplifier 10, and is connected to the output terminal TOS of the switch amplifier 8.
Are connected to the output port P.

The input matching circuit 2 of each of the amplifiers 8 and 10
3 and 33 are set to match the input impedances of the HEMTs 20 and 30, respectively. Further, the output matching circuit 36 of the limit amplifier 10 matches the input impedance of the switch amplifier 8 and The circuit 26 is set to match the input impedance of the transmitting antenna A connected to the output port P.

The switch amplifier 8 and the limit amplifier 10 use HEMTs 20 and 30 having the same characteristics, and the input matching circuits 23 and 33 have the same characteristics. The characteristics of the amplifiers 8 and 10 are determined by appropriately setting the output matching circuits 26 and 36 so that the saturation output power Pmax of the limit amplifier 10 is the input power when the small signal gain of the switch amplifier 8 is reduced by 1 dB. The gain compression power is set so as to be less than or equal to P (P ≧ Pmax).

In the signal supply device 2 of the present embodiment thus configured, the branch circuit 6 divides the high-frequency signal generated by the oscillator 4 into two equal parts, and divides the high-frequency signal into two equal parts CH1, CH2.
Feed to 2. Then, in each of the channels CH1 and CH2, the supplied high-frequency signal is input to the limit amplifier 10 via the input terminal TIL.

Then, both amplifiers 8, 10 of the same channel
When a control signal (drain bias voltage) is applied to both of the control terminals TCS and TCL, the branch line L becomes conductive as described below. That is, in the limit amplifier 10, the high-frequency signal input from the input terminal TIL is input to the HEMT 30 without being reflected by the matching operation of the input matching circuit 33, and is amplified by the HEMT 30. At this time, if the input power to the HEMT 30 has reached the saturation region, its output power is limited to the upper limit power Pmax. The output of the HEMT 30 supplied to the switch amplifier 8 via the output terminal TOL is input to the switch amplifier 8 without being reflected by the matching operation of the output matching circuit 36.

Then, in the switch amplifier 8, similarly to the limit amplifier 10, the high-frequency signal input via the input terminal TIS is input to the HEMT 20 without being reflected by the matching operation of the input matching circuit 23, and is input to the HEMT 20.
Is amplified. At this time, the input power to the HEMT 20 is equal to or less than the upper limit power Pmax by the limit amplifier 10,
That is, since the gain is limited to the gain compression power P or less, amplification is performed using only the linear region. And the output terminal TOS
The output of the HEMT 20 supplied to the transmission antenna A connected to the output port P via the output port P is input to the transmission antenna A without reflection by the matching operation of the output matching circuit 26. When waveform distortion is generated by the limit amplifier 10, harmonic components generated by the distortion are removed by the filter function of the switch amplifier 8 configured as a narrow-band amplifier.
Gives a formatted output.

On the other hand, when the drain bias voltage is not applied to the control terminals TCS and TCL of both amplifiers 8 and 10 of the same channel, the high-frequency signal input through the input terminals TIL and TIS becomes the HEMT 30 and Since the light is reflected at 20, the branch line L is cut off.

Therefore, in the transmitter configured using such a signal supply device 2, the voltage supply device DS for controlling the supply of control signals to the control terminals TCS and TCL is replaced with the two amplifiers 8 belonging to the same channel. The control signal may be simultaneously applied to each of the ten control terminals TCS and TCL.

As described above, in the signal supply device 2 according to the present embodiment, the limit amplifier 10 for limiting the input power to the switch amplifier 8 is provided before the switch amplifier 8 that conducts and cuts off the branch line L. Thus, the switch amplifier 8 operates only in the linear region.

Therefore, according to the signal supply device 2 of the present embodiment, even if the power of the high-frequency signal supplied to each of the channels CH1 and CH2 via the branch circuit 6 is large, the on / off ratio of the switch amplifier 8 is high. Is not deteriorated, and the limit amplifier 10 and the switch amplifier 8 are simultaneously
Are turned on and off, high-performance switching with a large on / off ratio can be performed.

In the signal supply device 2 of this embodiment, the switch amplifier 8 and the limit amplifier 10 are output matched by using HEMTs 20 and 30 having the same characteristics and input matching circuits 23 and 33 set to the same characteristics. Circuit 26,3
6 are different from each other, so that the switching performance can be made uniform and the design and manufacturing can be facilitated.

As described above, even if a high-frequency signal with a large power is input, the on / off ratio does not deteriorate and the configuration can be shared, so that it is suitable for MMIC, and the device needs to be downsized. It can be suitably used for a transmitter or the like of a vehicle-mounted radar device. Furthermore, the signal supply device 2 of the present embodiment
When the power supplied to each of the channels CH1 and CH2 is small, the limit amplifier 10 operates only in the linear region and operates as a normal amplifier. It can be suitably operated even in a small case.

In this embodiment, the limit amplifier 10
Although a control terminal TCL is also provided and ON / OFF control is performed by a control signal, a constant drain bias voltage may be applied to the limit amplifier 10 so that only the switch amplifier 8 performs ON / OFF operation. [Second Embodiment] Next, a second embodiment will be described.

The signal supply device 2a of the present embodiment differs from the signal supply device 2 of the first embodiment only in part in the configuration. Therefore, the same components are denoted by the same reference numerals, and description thereof is omitted. The following description focuses on the differences. That is, in the signal supply device 2a of the present embodiment, as shown in FIG. 2, except that the variable gain amplifier 11 (11a, 11b) is used instead of the limit amplifier 10 (10a, 10b),
The configuration is exactly the same as the signal supply device 2 of the first embodiment.

Further, the variable gain amplifier 11 has a HEMT 3
0 except that a gain adjustment terminal TGL for applying a gate bias voltage as a gain adjustment signal is provided between the input matching circuit 33 and the gate of the limit amplifier 10.
The configuration is exactly the same.

The signal supply device 2a according to the present embodiment thus configured not only operates exactly the same as the signal supply device 2 according to the first embodiment, but also appropriately sets the gate bias voltage applied to the adjustment terminal TGL. By doing so, the small signal gain of the variable gain amplifier 11 can be adjusted.

Therefore, according to the signal supply device 2a of this embodiment, not only the same effects as in the first embodiment can be obtained, but also
The small signal gain is adjusted according to the magnitude of the input power to the variable gain amplifier 11 so that the output power becomes equal to or less than the gain compression power P of the switch amplifier 8 and the variable gain amplifier 11 operates only in the linear region. For example, the upper limit power of the high-frequency signal input to the switch amplifier 8 can be limited without distorting the waveform, and a high-quality high-frequency signal with small distortion can be supplied to the outside via the output port P. . Third Embodiment Next, a third embodiment will be described.

The signal supply device 2a of the present embodiment differs from the signal supply device 2 of the first embodiment only in part in configuration. Therefore, the same components are denoted by the same reference numerals and description thereof is omitted. The following description focuses on the differences. That is, in the signal supply device 2b of the present embodiment, as shown in FIG. 3, except that the variable gain amplifier 12 (12a, 12b) is used instead of the limit amplifier 10 (10a, 10b).
The configuration is exactly the same as the signal supply device 2 of the first embodiment.

The variable gain amplifier 12 (12a, 12a)
b) shows the drain terminal of the HEMT 30 and the output matching circuit 3
6, the gate terminal is a DC cut capacitor 4
1, the HEMT 40 connected to the ground is connected, and the control terminal TCL provided between the stub 35 and the capacitor 38 is omitted. Instead, the HEMT 40 and the capacitor 41 are connected between the HEMT 40 and the capacitor 41 as a gain adjustment signal. The configuration is exactly the same as that of the limit amplifier 10 except that a gain adjustment terminal TGL for applying a gate bias voltage is provided. That is, the variable gain amplifier 12 of the present embodiment is
Are a pair of cascode-connected HEMTs 30, 40 instead of a single HEMT 30 as signal amplification elements.
(Hereinafter, referred to as cascode transistors).

In the signal supply device 2b of this embodiment having the above-described configuration, the variable gain amplifier 12 is always in operation regardless of the on / off state of the switch amplifier 8, and the control applied to the control terminal TCS of the switch amplifier 8 is controlled. Except that the conduction and cutoff of each channel CH1 and CH2 are controlled only by the signal, the operation is completely the same as that of the first embodiment.
As in the second embodiment, by appropriately setting the gain adjustment signal applied to the gain adjustment terminal TGL, the variable gain amplifier 1
2 small signal gain can be adjusted.

Therefore, according to the signal supply device 2b of this embodiment, not only the same effects as those of the first and second embodiments can be obtained, but also a pair of HEMTs 3
Since a cascode transistor composed of 0 and 40 is used, a variable range of the small signal gain can be secured to 20 dB or more.
As compared with the signal supply devices 2 and 2a of the first and second embodiments, it is possible to cope with a wider range of input power.

In this embodiment, the variable gain amplifier 12
The gate bias voltage of the HEMT 40 on the output side of the pair of HEMTs 30 and 40 forming the cascode transistor is changed as a gain adjustment signal for adjusting the small signal gain of the cascode transistor. The small signal gain may be adjusted by changing the amount of feedback in the negative feedback circuit.

The negative feedback circuit has a drain terminal connected to the source terminal of the HEMT 40 and a source terminal connected via a DC cut capacitor 43, for example, like the variable gain amplifier 13 (13a, 13b) shown in FIG. HEM
A HEMT 42 connected to the gate terminal of T30, the gate terminal of which is grounded via a DC cut capacitor 44.
In this case, a gain adjustment terminal TGL is provided between the HEMT 43 and the capacitor, and the HEMT 43 is provided.
The gate bias voltage at 42 may be used as the gain adjustment signal.

The HEMT 43 operates as a variable resistor, that is, the resistance between the drain and the source changes according to the gate bias voltage to change the feedback amount, thereby changing the small signal gain of the cascode transistor. It is. In this way, even in the variable gain amplifier 13 in which the negative feedback circuit is added to the cascode transistor, the variable range of the small signal gain can be secured to 20 dB or more, similarly to the variable gain amplifier 12 without the negative feedback circuit, and a wide input range can be obtained. It can respond to electric power. [Fourth Embodiment] Next, a fourth embodiment will be described.

The signal supply device 2c of the present embodiment is only partially different in configuration from the signal supply device 2 of the first embodiment. Therefore, the same components are denoted by the same reference numerals and description thereof is omitted. The following description focuses on the differences. That is, in the signal supply device 2c of the present embodiment, as shown in FIG. 5, the first except that the variable attenuator 14 (14a, 14b) is used instead of the limit amplifier 10 (10a, 10b).
The configuration is exactly the same as the signal supply device 2 of the embodiment.

The variable attenuator 14 has a pair of high-frequency lines 50 and 51 connected in series between its input terminal TIL and output terminal TOL, and a stub having one end connected between the high-frequency lines 50 and 51. 52 and the other end of the stub 52 (hereinafter, referred to as
A control terminal), a drain terminal is connected to the HEMT 53, and a source terminal is grounded. The gate terminal of the HEMT 53 is provided with an attenuation adjustment terminal TRL for applying a gate bias voltage as an attenuation adjustment signal. .

The length of the stub 52 is λ / 4 + n, where λ is the wavelength of the high-frequency signal generated by the oscillator 4 in the line.
Λ / 2 (n: 0 or a positive integer) is set, and when the control terminal is in the open state, the high-frequency signal is passed through the high-frequency line 51 as it is, while when the control terminal is in the ground state,
A high-frequency signal passing through the high-frequency line 51 is attenuated by reflection. That is, when the HEMT 53 is turned off by applying a negative voltage attenuation adjustment signal to the attenuation adjustment terminal TRL, the stub 52
Since the control terminal of the HEMT 5 is in an open state, the high-frequency signal is not attenuated.
When the switch 3 is turned on, the control end of the stub 52 is grounded, so that the high-frequency signal is attenuated.

Therefore, when the input power of the high-frequency signal supplied to each of the channels CH1 and CH2 is larger than the gain compression power P of the switch amplifier 8, the attenuation adjustment signal is made to cause the variable attenuator 14 to attenuate the signal. Just set it.
According to the signal supply device 2c of the present embodiment configured as described above, when the high-frequency signal is attenuated by the variable attenuator 14, the high-frequency signal is not distorted. A high-quality high-frequency signal can be supplied.

In the present embodiment, the length of the stub 52 is set to λ / 4 + n · λ / 2.
May be set. However, in this case, the high-frequency signal is
Since the control terminal attenuates when the control terminal is in the open state and passes as it is when the control terminal is in the ground state, it is necessary to perform control by reversing the polarity of the attenuation adjustment signal.

In this embodiment, the HEMT 53 is used to switch the state of the control end of the stub 52. However, as in the variable attenuator 15 (15a, 15b) shown in FIG. A diode whose end is connected to the cathode and whose anode is grounded may be used, and the attenuation adjustment terminal TRL may be provided between the stub 52 and the diode.

In this case, when the diode is turned on by applying a negative voltage attenuation adjustment signal to the attenuation adjustment terminal TRL, the control terminal of the stub 52 is grounded, while applying a positive voltage attenuation adjustment signal to activate the diode. When turned off, the stub 52
Is open, and the same operation and effect can be obtained as in the case where the HEMT 53 is provided. [Fifth Embodiment] Next, a fifth embodiment will be described.

The signal supply device 2d of the present embodiment is only partially different in configuration from the signal supply device 2 of the first embodiment. Therefore, the same components are denoted by the same reference numerals, and description thereof is omitted. The following description focuses on the differences. That is, in the signal supply device 2d of the present embodiment, each channel CH1, CH
2 includes a second branch circuit 7 that distributes the high-frequency signal supplied to the branch line L (L1, L2) to the pair of second branch lines LL1 and LL2 by power distribution, The pair of switch amplifiers 81 and 82 provided in each of the second branch lines LL1 and LL2 and the outputs of the switch amplifiers 81 and 82 are combined and the output port P
(P1, P2).

The switch amplifiers 81 and 82 are connected to the first
The configuration is exactly the same as the switch amplifier 8 of the embodiment. The signal supply device 2d of the present embodiment thus configured
Then, the branch circuit 6 distributes the power of the high-frequency signal generated by the oscillator 4 into two equal parts, and the pair of branch lines L (L1, L1
Supply to 2). Then, in each branch line L, the supplied high-frequency signal is further divided into two equal powers by the second branch circuit 7, and supplied to the pair of second branch lines LL1 and LL2.
The signal is input to the switch amplifiers 81 and 82 provided in each of the second branch lines LL1 and LL2.

Then, each switch amplifier 81, 82
According to the control signal applied to the control terminal TCS, the second branch lines LL1 and LL2 are turned on and off, respectively, and the combining circuit 9 combines the outputs from the switch amplifiers 8 and outputs the output port P (P1, Transmitting antenna A connected to P2)
(A1, A2).

The voltage supply device DS generates a control signal to be applied to the control terminal TCS so that the pair of switch amplifiers 81 and 82 of one of the channels is simultaneously turned on. As described above, in the signal supply device 2d of the present embodiment, the pair of switch amplifiers 8 share conduction and cutoff of the high-frequency signal in parallel for each of the channels CH1 and CH2. The input power to 81 and 82 is half the input power to each channel CH1 and CH2.

Therefore, if the output power of the high frequency signal generated by the oscillator 4 is not more than twice the gain compression power P of the switch amplifiers 81 and 82, the switch amplifiers 81 and 82 can be switched without deteriorating the on / off ratio. Since the switch amplifiers 81 and 82 amplify using only the linear region, high-quality high-frequency signals with small distortion can be supplied through the output ports P1 and P2.

Further, in this embodiment, since the high-frequency signal is not forcibly saturated or attenuated, the input power is not wasted, and a device having excellent power use efficiency can be constructed. In this embodiment, each channel C
A pair of switch amplifiers 81 and 82 are provided for each of H1 and CH2. The number of switch amplifiers, that is, the number of branches in the second branch circuit 7 is determined by the magnitude of the input power to each channel CH1 and CH2. , Any number of input powers to each switch amplifier may be set as long as they are set to be equal to or less than the gain compression power P.

Although some embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be implemented in various modes without departing from the gist of the invention. It is. For example, in each of the above embodiments,
Although it was configured to supply a two-channel high-frequency signal,
The configuration may be such that three or more channels, that is, the number of branches in the branch circuit 6 is three or more.

Further, as in the second to fourth embodiments, a variable gain amplifier or a variable attenuator is provided in the preceding stage of the switch amplifier, and the loss in the transmission line reaching the variable gain amplifier or the variable attenuator is obtained. Are different from each other between the channels, the small signal gain of the variable gain amplifier or the attenuation of the variable attenuator is set for each channel so that the input power to the switch amplifier is constant according to the loss. The amounts may be set differently.

Further, in the above-described embodiment, the signal supply device is shown, but a portion corresponding to the switch means, that is, in the first embodiment, the switch amplifier 8 and the limit amplifier 10, and the second and third embodiments. In the example, the switch amplifier 8 and the variable gain amplifier 11 or 12 or 13 are combined. In the fourth embodiment, the switch amplifier 8 and the variable attenuator 14 or 15 are combined. In the fifth embodiment, the switch amplifier 8 and the second branch circuit 7 are combined. It may be configured as a high-frequency switch device in which only the circuit 9 is extracted.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a two-channel high-frequency signal supply device according to a first embodiment.

FIG. 2 is a configuration diagram of a two-channel high-frequency signal supply device according to a second embodiment.

FIG. 3 is a configuration diagram of a two-channel high-frequency signal supply device according to a third embodiment.

FIG. 4 is a modification of the third embodiment.

FIG. 5 is a configuration diagram of a two-channel high-frequency signal supply device according to a fourth embodiment.

FIG. 6 is a modification of the fourth embodiment.

FIG. 7 is a configuration diagram of a two-channel high-frequency signal supply device according to a fifth embodiment.

FIG. 8 is a graph showing characteristics of a switch amplifier and a limit amplifier.

FIG. 9 is a graph showing a simulation result of a waveform shaping operation of the switch amplifier.

FIG. 10 is an explanatory diagram illustrating an operation of a variable gain amplifier.

FIG. 11 is an explanatory diagram for understanding that transmission loss occurs for each transmission line.

[Explanation of symbols]

2, 2a to 2d 2-channel high-frequency signal supply device 4 oscillator 6 branch circuit 7 second branch circuit 8, 81, 82 switch amplifier 9 synthesis circuit 10 limit amplifier 11, 12, 13 variable gain amplifier 14, 15 ... variable attenuator 22, 25, 32, 35,
52 stubs 21, 24, 31, 34, 50, 51 high-frequency lines 23, 33 input matching circuits 26, 36 output matching circuits 27, 28, 37, 38, 41, 43, 44 capacitors A1, A2 Antenna DS ... Voltage supply device L
1, L2 branch line LL1, LL2 second branch line P1, P2 output port

Continued on the front page F-term (reference) 5J067 AA01 AA04 AA21 AA41 CA21 FA01 FA10 HA12 HA19 HA22 HA25 HA26 HA29 KA00 KA20 KA23 KA29 KA32 KA68 KS01 KS11 LS01 MA13 MA17 SA14 TA01 TA02 TA06 5J069 AA01 HA21 HA21 HA25 HA26 HA29 KA00 KA20 KA23 KA29 KA32 KA68 MA13 MA17 SA14 TA01 TA02 TA06 5J092 AA01 AA04 AA21 AA41 CA21 FA01 FA10 HA12 HA19 HA22 HA25 HA26 HA29 KA00 KA20 KA23 KA29 KA32 KA68 MA13 MA17 TA06 TA01

Claims (17)

[Claims] An oscillator for generating a high-frequency signal using a Gunn diode; a branch circuit for supplying the high-frequency signal generated by the oscillator to each of branch lines reaching a plurality of output ports; And a switching means for conducting and blocking the branch line in response to an external control signal; and a multi-channel high-frequency signal supply device for supplying a high-frequency signal through each of the output ports. A switching amplifier configured to reflect or amplify and pass a high-frequency signal supplied from the branch circuit to the branch line in accordance with the control signal; and an upper limit power of the high-frequency signal input to the switch amplifier. A multi-channel high-frequency signal supply device, comprising: 2. The apparatus according to claim 1, wherein the upper limit power limited by the limiting unit is set to be equal to or less than a gain compression power which is an input power when a small signal gain of the switch amplifier is reduced by 1 dB. The multi-channel high-frequency signal supply device according to claim 1. 3. The limiting means comprises a limit amplifier configured to amplify a high-frequency signal supplied to the branch line and to set the amplified output to be saturated at the upper limit power. 3. The multi-channel high-frequency signal supply device according to claim 1 or claim 2. 4. The multi-channel high-frequency signal supply device according to claim 3, wherein said limit amplifier is started and stopped in accordance with conduction and interruption of said branch line by said switch amplifier. 5. The multi-channel high-frequency signal supply device according to claim 4, wherein both the switch amplifier and the limit amplifier are configured using transistors having the same characteristics. 6. The multi-channel high-frequency signal supply device according to claim 5, wherein both the switch amplifier and the limit amplifier are configured using input matching circuits having the same characteristics. 7. The multi-channel high-frequency signal supply device according to claim 1, wherein said limiting means comprises a variable gain amplifier capable of adjusting a small signal gain by an external gain adjustment signal. 8. The variable signal amplifier includes a transistor having a source terminal grounded, and changing a voltage applied to a drain terminal or a gate terminal of the transistor in accordance with the gain adjustment signal to thereby obtain the small signal gain. The multi-channel high-frequency signal supply device according to claim 7, wherein? 9. The variable gain amplifier includes a pair of cascode-connected transistors, wherein a voltage applied to a gate terminal of an output-side transistor of the pair of transistors is changed in accordance with the gain adjustment signal. The multi-channel high-frequency signal supply device according to claim 7, wherein the small signal gain changes. 10. The variable gain amplifier, comprising: a pair of cascode-connected transistors; and a variable resistor that connects an input and an output of the pair of transistors to form a negative feedback circuit. The multi-channel high-frequency signal supply device according to claim 7, wherein the small signal gain changes by changing a resistance value according to the gain adjustment signal. 11. The variable resistor comprises a transistor having a drain terminal and a source terminal connected to a feedback source and a feedback destination of the negative feedback circuit, and a gate terminal to which the gain adjustment signal is applied. The multi-channel high-frequency signal supply device according to claim 10. 12. The multi-channel high-frequency signal supply device according to claim 1, wherein said limiting means comprises a variable attenuator whose attenuation can be adjusted by an external attenuation adjustment signal. . 13. The variable attenuator comprises: a stub having one end connected to a branch line; and a transistor for grounding and opening the other end of the stub, wherein the voltage applied to a gate terminal of the transistor is attenuated. 13. The multi-channel high-frequency signal supply device according to claim 12, wherein the amount of attenuation changes by changing the amount of attenuation in accordance with the adjustment signal. 14. The variable attenuator, comprising: a stub having one end connected to a branch line; and a diode having a cathode connected to the other end of the stub and an anode grounded, and a voltage applied to the diode. 13. The multi-channel high-frequency signal supply device according to claim 12, wherein the amount of attenuation changes by changing the amount of attenuation in accordance with the attenuation adjustment signal. 15. An oscillator for generating a high-frequency signal using a Gunn diode, a branch circuit for supplying the high-frequency signal generated by the oscillator to each of branch lines reaching a plurality of output ports, and the branch line A multi-channel high-frequency signal supply device, comprising: a switching unit that conducts and cuts off the branch line in response to an external control signal. A second branch circuit that supplies a signal to each of the plurality of second branch lines provided; a high-frequency signal provided to each of the second branch lines and supplied from the second branch circuit to the second branch line To
A switch amplifier that reflects or amplifies and passes the signal in accordance with the control signal; and a combining circuit that combines the outputs of the switch amplifiers provided for each of the second branch lines and outputs the combined output as the output of the switching unit. A multi-channel high-frequency signal supply device characterized by the above-mentioned. 16. The number of branches by the second branch circuit is such that a high-frequency signal supplied to each of the second branch lines is
16. The multi-channel high-frequency signal supply device according to claim 15, wherein the small signal gain of the switch amplifier is set to be equal to or less than a gain compression power which is an input power when the small signal gain is reduced by 1 dB. 17. A transmission line provided for a high-frequency signal,
What is claimed is: 1. A high-frequency switching device that conducts or cuts off said transmission line in response to a control signal from outside, comprising: a switch amplifier that reflects or amplifies and passes a high-frequency signal supplied to said transmission line in accordance with said control signal; And a limiting means for limiting the upper limit power of the high frequency signal input to the switch amplifier.