JPH11186803A - High frequency switch circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high frequency switch circuit low in a loss and high in isolation. SOLUTION: A line from a prescribed input terminal 10 to a branch point 14 is a single line in the case of one input/multi-outputs and each of branch lines 15A, 15B in a gap from the branch point 14 to plural output terminals 7A, 7B is respectively provided with transmission lines 8A, 8B having about 1/4 wavelength of the utilizing frequency, switching circuits 20A, 20B and amplifiers 5A, 5B. Each of the switching circuits 20A, 20B is provided with a PIN diode 1. The PIN diode 1 is turned off in an ON-path based on a control signal from a switch ON/OFF control circuit 22 to interrupt the gap between the transmission line 8A, 8B and a high frequency ground 2 and is turned on in an OFF-path to make the gap in a short-circuit state. The amplifier 5A, 5B are connected between a connecting point (of the corresponding transmission line 8A (8B) with the switching circuit 20A (20B)) and the output terminal 7A (7B). The amplifier 5A, 5B perform ON-OFF operation based on a control signal supplied as an amplifier power supply bias, amplify a high frequency signal in the ON-path and do not amplify a leaked high frequency signal in the OFF-path.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency switch circuit used for communication equipment and the like, for switching and using a plurality of branch lines.

[0002]

2. Description of the Related Art [Conventional Configuration 1] A switch circuit using a PIN diode having a small loss and excellent isolation characteristics is used as a switch circuit for communication equipment for microwave communication. In the switch circuit shown in FIG. 6, the input terminal 10 branches into a plurality of lines from the branching unit 34 via a single line. Each of the branched lines is a transmission line 38 (38
a1, a2,..., 38b1, b2,.
0 (40a1, a2,..., 40b1, b2,...) Are provided.
In this high-frequency switch circuit, as shown in FIG. 6, a circuit 15 including one transmission line 38 and one switching circuit 40 is connected in multiple stages to each branch line 35 (35a, 35b,...). Has been adopted.

Next, one stage of the circuit 15 (15-1)
The operation will be described with reference to an example. Multiple branch lines 35
In the path to be turned off (branch line 35a in FIG. 6) out of a and 35b, the switching circuit 40a1 is short-circuited. Specifically, a terminal of the anode bias circuit 32,
A predetermined control signal is applied from the switch on / off control circuit 50 to the control bias terminal of the control bias circuit of the switching circuit 40a1 to be turned on. As a result, the PIN diode 1 becomes conductive, the switching circuit 40a1 becomes short-circuited, and the branch point 34 to the output terminal 7a
Create an open state when looking at the side. This allows input terminal 1
The high-frequency signal passing through the transmission line 38a1 having a wavelength of about 0 to about 1/4 is not guided to the output terminal 7a. On the other hand, in the path to be turned on (35b in FIG. 6), the switching circuit 40b1
Is turned off, the high-frequency signal from the input terminal 10 is output from the output terminal 7b through the branch line 35b. After a predetermined period, another branch line 35 (for example, the branch line 35a) is turned on, and the remaining paths are turned off. By performing such driving, it is possible to switch the branch line and generate a signal from the input terminal from a different output terminal.

However, in practice, the switching circuit 40
Because of the parasitic element existing at a1, the output terminal 7a is not completely open when viewed from the branch point 34 toward the output terminal 7a, and the input terminal 1
Signal power supplied from 0 leaks to the off path. For this reason, the input terminal 10 and the output terminal 7a in the off path
High isolation cannot be obtained between them. Therefore, in the configuration shown in FIG. 6, the circuits 15 are connected in multiple stages to improve the isolation. That is, for example, the signal power leaked 1/10 in the first stage 15-1
At -2, the signal power is further reduced to 1/10. By such a method, a high isolation characteristic of 1/100 is obtained as a whole (see Japanese Patent Application Laid-Open No. 7-245502).

[Conventional configuration 2] As another switch structure, for example, as shown in Japanese Patent Application Laid-Open No. 1-248706, an amplifier is provided in a single input / output path, and the amplification degree of the amplifier is provided. A configuration is known in which a high-frequency signal supplied to an input terminal is switched on and off by controlling a voltage applied to a power supply bias terminal for determining the power supply bias terminal.

[0006]

(I) In the high-frequency switch shown in FIG. 6, the switching circuit 40 (40b1, 40b2) is opened in the path to be turned on, but the switching circuit 40 is parasitic as described above. The high-frequency signal leaks to the high-frequency ground 2 by the parasitic element. Therefore, the leakage to the high-frequency ground becomes a loss for the ON path. This loss increases as the number of connection stages of the circuit 15 increases. In other words, the more the number of connection stages of the circuit 15 is increased in order to increase the isolation of the path to be turned off,
There is a problem that the loss of the path to be turned on increases.

In the high-frequency switch shown in FIG. 6, a high-frequency signal leaking to the off path is also a loss for the other on path, and the loss increases as the number of branches (the number of off paths) increases. There is also a problem that.

(Ii) The conventional configuration 2 is a switch configuration for turning on / off a single line. On the basis of this switch configuration, a plurality of route switching switches are required.
A means for splitting the high-frequency signal is required. FIG. 7 shows a configuration example of a one-input two-switch output switch using the conventional configuration 2. Each branch line that branches into two from the branch point 34 includes:
Amplifiers 65 (65a, 65b) are provided, respectively, and the amplifier power supply bias terminals 66 (66a, 66b) are supplied from output terminals 7 (7a, 7b) in response to a control signal supplied from a switch on / off control circuit 70. The output of the high frequency signal is switched.

In general, when an amplifier is used for high-frequency switching, it is designed such that the reflection coefficient is zero on both the input and output sides in the frequency band where the gain is at or near the maximum in consideration of the connection with the preceding and succeeding stages. A matching circuit 60 is incorporated.

However, when a bias voltage such that the high frequency signal is turned off by the amplifier is applied to the bias terminal 66, the reflection coefficient of the amplifier 65 seen from the input side is slightly increased, but the amplifier 65 is in the open state as in the conventional configuration 1. No.
Therefore, if the switch is constituted only by the amplifier 65, the amplifiers having substantially the same small input reflection coefficient (<0.3) regardless of ON / OFF from the branch point 34 are only connected in parallel, and a single line The impedance seen decreases. Therefore, there is a problem that a matching circuit 60 corresponding to the number of branches is required on the single line side.

[0011] To solve the above problems, the present invention provides:
It is an object of the present invention to provide a high-frequency switch circuit that does not require a matching circuit on the single line side and is capable of achieving both high isolation characteristics in an off path and low loss characteristics in an on path.

[0012]

In order to achieve the above object, a high-frequency switch circuit according to the present invention comprises a plurality of branch lines separated from a branch point, each of which has a transmission line having a wavelength of about 1/4 wavelength. A switching circuit that is connected to one end of the transmission line and that performs an on / off operation based on a predetermined control signal to switch a short-circuit / interrupt state between the transmission line and ground; A high-frequency signal on a branch line is amplified or de-amplified by being turned on / off based on a predetermined control signal supplied as an amplifier power supply bias, which is connected between a connection point with a circuit and an input terminal or an output terminal. And an amplifier to perform. Then, the switching circuit of any one of the plurality of branch lines is set to the cutoff state and the amplifier is set to the amplification state, and the switching circuit of the remaining branch line among the plurality of branch lines is The amplifier is in a short-circuited state and the amplifier is in a non-amplified state.

In the ON path of the plurality of branch lines, the loss of the high-frequency signal caused by the parasitic element existing in the switching circuit can be compensated for by the amplification operation of the amplifier. On the other hand, in the off path, the leakage of the high-frequency signal to the output side caused by the parasitic element existing in the switching circuit is attenuated by the non-amplifying operation of the amplifier. As a result, the loss can be reduced in the ON path and the isolation can be increased in the OFF path.

In addition, a switch circuit having a reflection coefficient of 0.5 to 1.0 for both the ON state and the OFF state and a phase difference between the ON state and the OFF state within a range of 180 ° ± 40 ° is used. Thus, the matching state as viewed from the connection point between the ON path and the OFF path is 0.2 or less in reflection coefficient, and a matching circuit can be eliminated.

[Other Embodiments of the Present Invention] Other embodiments of the present invention include the following.

(I) The present invention is applicable to a single-input multi-switch output type transmission line, wherein a single line is provided between an input terminal and a branch point, and a branch line extends from the branch point to a plurality of output terminals;
A control circuit that outputs a control bias signal and a power supply bias signal that are simultaneously turned on / off as a control signal, wherein each of the branch lines is a transmission line similar to the above,
It has a switching circuit and an amplifier. Further, the control of the switching circuit and the amplifier is performed in the same manner as the control described above, in which the switching circuit of any one of the plurality of branch lines is set to the cutoff state and the amplifier is set to the amplification state, and the control of the plurality of branch lines is performed. The switching circuits of the remaining branch lines are short-circuited, and the amplifier is in a non-amplified state.

(Ii) Other branch lines of a multi-switch input-one output type transmission line or a multi-switch input / multi-switch output type transmission line, for example, an input side branch line and an output side branch line,
A transmission line, a switching circuit, and an amplifier similar to the above are provided. Control of the switching circuit and the amplifier is as follows:
This is the same as the above control.

(Iii) Each switching circuit has a reflection coefficient of 0.5 in both the ON state and the OFF state of the switch circuit.
The phase difference between the ON state and the OFF state is 180 degrees ± 1.0
A switching element having characteristics within a range of 40 degrees is provided. As this switching element, for example, a PIN diode, a field effect transistor (FET), a varicap element, or the like can be used.

If a switching circuit having such characteristics is used, the matching state of the on-path and the off-path of the branch line as viewed from the branch point is 0.2 or less in reflection coefficient, and the matching circuit is provided on the single line side. Do not need.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention (hereinafter, referred to as embodiments) will be described below with reference to the drawings.

[Embodiment 1] FIG. 1 shows an example of a high-frequency switch circuit according to an embodiment of the present invention. Here, a configuration in which a single input line is branched into two lines is shown. In FIG. 1, an anode bias circuit 9 having an anode bias terminal 18 for applying a bias to an anode of a PIN diode 1 described later is connected to a single line from an input terminal 10 to a branch point 14. The end branches off into two branch lines 15. Each branch line 15
(15A, 15B) are circuits 16 each having the same configuration.
(16A, 16B), and the circuit 16 includes a microstrip transmission line 8 of about １ ／ wavelength of the used frequency.
(8A, 8B) and the switching circuit 20 (20A, 20A).
B) Further, the switching circuit 20 and the output terminal 7 (7A,
7B) is provided with the amplifier 5 (5A, 5B).

Switching circuit 20 of each branch line 15
Has a PIN diode 1 and a control bias circuit 3. The PIN diode 1 has an anode connected to the end of the corresponding microstrip transmission line 8 and a cathode grounded to the high-frequency ground 2. The control bias circuit 3 is connected to the cathode of the PIN diode 1, and applies a bias voltage corresponding to a control signal applied from the switch on / off control circuit 22 to the control bias terminals 17 (17A, 17B). And each PI
The operation of the N diode 1 is controlled by a combination of an anode bias terminal 18 and a voltage applied to the control bias terminal 17A or 17B.

The input side of each amplifier 5 is connected to the anode side of the PIN diode 1 of the corresponding switching circuit 20, and the output side of each amplifier 5 is connected to the output terminal 7. Further, the amplifier 5 has an amplifier power supply bias terminal 6 (6A, 6B) for applying a bias voltage for operating the amplifier, and a predetermined control signal from the switch on / off control circuit 22 is applied to the terminal 6. As a result, the operation of the amplifier 5 is controlled.

Next, the operation of the high-frequency switch circuit having the above configuration will be described. Here, it is assumed that the branch line 15A is an off-path and the branch line 15B is an on-path in a certain phase. In the off path (the branch line 15A in FIG. 1), the anode bias terminal 18 and the control bias terminal 17
During the period A, that is, between the anode and the cathode of the PIN diode 1, a bias voltage that makes the PIN diode 1 of the switching circuit 20A conductive is selectively applied based on the switch on / off control circuit 22. Therefore, at the connection point 13A of the PIN diode 1, the high-frequency signal input from the input terminal 10 is
With the presence of the microstrip transmission line 8A of about 1/4 wavelength, the circuit 16A side is open at 0 degree in the total reflection state when viewed from the branch point 14. Therefore, the high-frequency signal input from the input terminal 10 is not guided to the circuit 16A.

Here, due to the parasitic resistance of the PIN diode 1 when the PIN diode 1 is in the conductive state, the PIN diode 1 does not actually become an ideal short circuit, and a high-frequency signal leaks from the connection point 13A to the output side ( In the simulation, the isolation between the input terminal 10 and the connection point 13A is 18.
0 dB). However, since the amplifier 5A can obtain the isolation characteristic in the non-amplifying operation state, the high-frequency signal leaked from the PIN diode 1 applies a bias voltage to the power supply bias terminal 6A so that the amplifier 5A is in the non-amplifying operation state. By doing so, the leakage of the high frequency signal to the output terminal 7A is further attenuated (in the simulation, the isolation between the input terminal 10 and the output terminal 7A is 4
0.6 dB).

One ON path (branch line 15B in FIG. 1)
Now, the anode bias terminal 18 and the control bias terminal 1
7B, a bias voltage is applied such that the PIN diode 1 of the switching circuit 20B is turned off. As a result, the high-frequency signal input from the input terminal 10 is not guided to the high-frequency ground 2 via the PIN diode 1 of the switching circuit 20B, but the amplifier 5B
It is led to. At this time, a bias voltage is applied to the power supply bias terminal 6B of the amplifier 5B from the switch-on / off control circuit 22 so that the amplifier 5B performs an amplifying operation. The high-frequency signal passes through the amplifier 5B, is amplified, and is output to the output terminal 7B. Appear. The loss caused by the leakage of the high-frequency signal to the high-frequency ground 2 due to the parasitic capacitance of the PIN diode 1 when the PIN diode 1 is in the non-conducting state and the loss caused by the leakage to the circuit 16A on the off-path side (in the simulation, The loss between the input terminal 10 and the connection point 13B is 1.8.
dB), the gain is compensated by the gain obtained by the amplification operation in the amplifier 5B, and a positive gain is generated overall (in the simulation, the gain between the input terminal 10 and the output terminal 7B is 4.2 dB).

The control bias voltage for the PIN diode 1 of the switching circuit 20A and the PIN diode 1 of the switching circuit 20B, and the power supply bias for the amplifiers 5A and 5B are changed in conjunction with each other to switch the respective operation states. Specifically, the PIN diode 1 of one circuit 16 is in a conductive state, the corresponding amplifier 5 is in a non-amplifying operation state, the PIN diode 1 of the other circuit 16 is in a non-conductive state, and the corresponding amplifier 5 is in an amplifying operation state. I do. The control bias voltage and the amplifier power supply bias voltage are applied to the corresponding terminals 17 and 6 so that the operating states of the PIN diode 1 and the amplifier 5 are in such a combination.
, It is possible to switch the output destination of the high-frequency signal input from the input terminal 10 to one of the output terminals 7A and 7B. These two types of bias voltages can be controlled by a predetermined control signal applied from the switch on / off control circuit 22 to each terminal.

FIG. 2 shows the characteristic impedance Z of the transmission line.
2 shows an example of the impedance of each part in FIG. 1 and the condition of the switching circuit when = 50Ω. Here, the branch line 15A is an ON path, the branch line 15B is an OFF path, and the reflection coefficient of the switching circuit 20A (OFF) is 1..
0, the phase is 0 °, the reflection coefficient of the switching circuit 20B is 1.0, and the phase is 180 °. Amplifier 5A, 5
The input impedance of B is 50Ω. The input impedance to the switching circuit is almost infinite on the ON path and almost 0 on the OFF path. Looking at the two paths after the branching section, the input impedance of the off path is infinite and the input impedance of the on path is 5
0 Ω (here, equal to the input impedance of the amplifier). As described above, the off path after the branching portion is almost electrically open (Z ≒ ∽), and hardly affects the impedance of the on path. Therefore, a matching circuit is not required on the single line side as shown in FIG. 7 (in the simulation, the reflection coefficient viewed from the input terminal is 0.05). The on-state and off-state reflection coefficients of the switching circuits of the branch lines 15A and 15B are both 0.5 to 0.5.
1.0, phase difference between ON state and OFF state is 180 ° ± 40
The condition of ゜ corresponds to the VSWR (voltage
This is a condition that the standing wave ratio (voltage standing wave ratio) satisfies 1.5 or less (0.2 or less in terms of reflection coefficient).

Next, at 60.5 GHz, a thickness of 20
A microstrip transmission line formed on an alumina substrate having a relative dielectric constant of 9.8 and a reflection coefficient of 0.8 in an ON state.
7, a PIN diode having a reflection coefficient of 0.83 in an off state, a phase difference of 170 degrees between an on state and an off state, a gain of 5.9 dB, and an isolation of 23.1 in a non-amplifying operation.
A simulation result when the above-described circuit of Embodiment 1 of the present invention shown in FIG. 1 is configured using the dB amplifier and a simulation result when the circuit of the conventional configuration 1 shown in FIG. It is shown in FIG.

[0030]

[Table 1] A microstrip transmission line fabricated on a substrate and a PIN diode having a reflection coefficient of 0.87 in the on state, a reflection coefficient of 0.83 in the off state, a phase difference of 170 degrees between the on and off states, and a gain Using an amplifier having 5.9 dB and an isolation of 23.1 dB during non-amplification operation,
Table 1 shows the simulation results when the above-described circuit of Embodiment 1 of the present invention shown in FIG. 1 is configured and the simulation results when the circuit of the conventional configuration 1 shown in FIG.

[0030]

[Table 1] As shown in Table 1, the gain of the ON path (between the terminal 10 and the terminal 7B) of the first embodiment (FIG. 1) is +4.2.
In contrast, the gain of the ON path (between the terminal 10 and the terminal 7b) of the conventional configuration 1 (FIG. 6) is -2.0 dB.
And the loss is improved by 6.2 dB. Further, while the isolation of the off path (between the terminal 10 and the terminal 7A) of the first embodiment is 40.6 dB, the conventional configuration 1
Is 34.4 dB (between the terminal 10 and the terminal 7a) in the off path, and the isolation is 6.2.
The dB has been improved. That is, according to the present embodiment, the isolation can be increased while the loss is reduced.

In the first embodiment, an example is shown in which a PIN diode is used as a switching circuit. However, both the ON state and the OFF state satisfy a reflection coefficient of 0.5 to 1.0, and the ON state Any switching element may be used as long as the phase difference between the off state and the off state is 180 degrees ± 40 degrees. Schottky barrier diode, FE as an example of the switching element
T, varicap, etc. are applicable. In addition, FET
In this case, the drain is connected to the connection point 13 in FIG. 1, the source is connected to the high-frequency ground 2, the gate bias circuit is connected to the control bias circuit 3, and the anode bias circuit 9 is removed. In the case of a varicap, one terminal of the varicap is connected to the connection point 13, the other terminal of the varicap is connected to the high frequency ground 2, the varicap bias circuit is connected to the control bias circuit 3, and the anode bias circuit 9 is connected. Removed configuration. In addition, passive elements such as inductors are additionally connected to these switching elements in series or in parallel, so that the on-state and the off-state both have a reflection coefficient of 0.5 to
At 1.0, the phase difference between the ON state and the OFF state is 180 degrees ± 40
The same effect can be obtained in a switching circuit having a high degree.

[Embodiment 2] In Embodiment 2, an amplifier 5 arranged outside a block 12 shown by a dotted line in FIG.
This is a two-switch input-one output switch circuit in which the connection direction of (5A, 5B) is reversed and the flow of the high-frequency signal is reversed from that of the first embodiment. FIG. 3 shows an example in which one branch line is turned off and the other is turned on in the high-frequency switch circuit of the second embodiment. In FIG. 3, parts corresponding to those in FIG. 1 described above are denoted by the same reference numerals. However, the signal flow is opposite to that of FIG. 1, and two input terminals are represented as IN7A and IN7B, respectively, and one output terminal is O
It is represented as UT10.

In the switch circuit shown in FIG. 3, a high frequency signal supplied to each input terminal IN7 (7A, 7B) is supplied to the ON path (in FIG. 3, the branch line 15B) by the amplification operation of the amplifier 5B. The signal is amplified, and the PIN diode 1 of the switching circuit 20B is turned off. In the off route (branch line 15A in FIG. 3),
The high frequency signal is attenuated by the non-amplifying operation of the amplifier 5A, and the PIN diode 1 of the switching circuit 20A is short-circuited.

In this configuration, as in the first embodiment, the loss can be reduced in the ON path and the isolation can be increased in the OFF path. Further, as in the first embodiment, the off path viewed from the branch point 14 can be almost electrically opened by the operation of the switching circuit, and therefore, the single line side (the branch point 14 and the output terminal OUT of the second embodiment).
10) is not required.

[Third Embodiment] FIG. 4 shows an example of a high-frequency switch circuit according to a third embodiment. The feature of the third embodiment is that the connection direction of the amplifier 5B of the first embodiment (FIG. 1) is reversed. In FIG. 4, FIG.
The components corresponding to are denoted by the same reference numerals. However, FIG.
, The branch line 15A is a line having the same signal propagation direction as that of FIG. 1, while the branch line 15B is a line having the same signal propagation direction as that of FIG. 3 (substantially the opposite direction of FIG. 1).

In the third embodiment, each branch line 15A,
The operation of each of the terminals 15B is the same as that of the first and second embodiments.
The direction of propagation of the signal passing through 0 also changes. This switching is performed by the switch on / off control circuit 22 and each bias terminal 1
8, 17A, 17B, 6A, 6B. The third embodiment can be applied, for example, as a transmission / reception switch when the same antenna is used for both transmission and reception.

In the third embodiment as well, the switching circuit 20 and the amplifier are connected to each branch line. As in the other embodiments, the loss is small in the ON path and the isolation is small in the OFF path. Can be higher. Further, similarly to the first embodiment, the off path viewed from the branch point 14 can be almost completely opened, so that the terminal 1
No matching circuit is required on the single line side between 0 and the branch point 14.

In each of the embodiments described above, a two-branch high-frequency switch circuit has been described. However, even if the number of branches is three or more, the effect of low loss and high isolation and the configuration that does not require a matching circuit are the same. Is obtained.

[Fourth Embodiment] FIG. 5 shows a switch circuit according to a fourth embodiment. The fourth embodiment is a switch circuit having two switching inputs and two switching outputs.
The switch circuit has a configuration in which a switch circuit having a switching output and a switch circuit having two switching inputs according to the second embodiment are combined. In FIG. 5, the input side includes two input terminals IN7A and IN7B.
And two branch lines 29A and 29B for transmitting the signals supplied from the respective branch lines 29 (29A and 29B).
B) includes a switching circuit 24 (24) as in FIG.
A, 24B), an amplifier 25 (25A, 25B), a transmission line 28 (28A, 28B) of about 1/4 wavelength of the working frequency
Is provided.

The input-side branch point 14IN and the output-side branch point 14
OUT and a single line, and the output side branch point 14
The output-side branch line 15 (15A, 15A)
The configuration of B) is the same as that of FIG. Also, input side branch point 1
Each switching circuit 20 (20A, 20B) and 2 has a single path between 4IN and the output side branch point 14OUT.
Anode bias circuit 9 for applying a bias voltage to the anode of PIN diode 4 (24A, 24B)
Is connected. The switch on / off control circuit 22 includes the switching circuits 20, 24 and the amplifier 5,
A predetermined control signal is supplied to each of the 25 bias terminals to control the operation.

In the above configuration, the input terminal IN
The high-frequency signal input from 7A passes through the branch line 29A,
It is possible to select a total of four types of routes, that is, whether the signal is transmitted to the output terminal OUT7A or the output terminal OUT7B or the high-frequency signal input from the input terminal IN7B is transmitted to the output terminal OUT7A or the output terminal OUT7B via the branch line 29B. Becomes The on-path selected based on the control signal from the switch-on / off control circuit 22 can have a low loss, and the off-path can have high isolation. Isolation can be improved and a matching circuit can be eliminated.

Even if the input side and the output side have three or more branches, the effect of low loss and high isolation and a configuration that does not require a matching circuit can be obtained in the same manner.

[0043]

According to the present invention, each transmission line having a wavelength of about 1/4 of the used frequency, a switching circuit,
Further, an amplifier is provided, and the switching circuit and the operation of the amplifier (amplifier power supply bias voltage) are controlled to turn on / off signal transmission on each branch line. It is possible to achieve both high isolation characteristics of the path.

Further, a switching circuit having a reflection coefficient of 0.5 to 1.0 for both the ON state and the OFF state and a phase difference between the ON state and the OFF state within a range of 180 ° ± 40 ° may be used. For example, it is possible to eliminate the matching circuit on the single line side.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a high-frequency switch circuit according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of conditions of the impedance and the switching circuit of each unit in FIG. 1;

FIG. 3 is a diagram illustrating a configuration of a high-frequency switch circuit according to a second embodiment.

FIG. 4 is a diagram illustrating a configuration of a high-frequency switch circuit according to a third embodiment.

FIG. 5 is a diagram illustrating a configuration of a high-frequency switch circuit according to a fourth embodiment.

FIG. 6 is a diagram showing a configuration of a conventional switch circuit.

FIG. 7 is a diagram showing a configuration of a multi-output type switch circuit that can be considered from a conventional configuration.

[Explanation of symbols]

1 PIN diode, 2 high frequency ground, 3 control bias circuit, 5, 5A, 5B amplifier, 7, 7A, 7
B output terminal, 9 anode bias circuit, 10 input terminal, 12 blocks, 14 branch points, 15, 15A,
15B branch line, 20, 20A, 20B switching circuit, 22 switch on / off control circuit.

Claims (1)

[Claims] 1. A plurality of branch lines separated from a branch point, a transmission line of about 波長 wavelength of a used frequency, and one end of the transmission line, which is turned on / off based on a predetermined control signal. A switching circuit that operates to switch a short-circuit / shut-off state between the transmission line and ground; an amplifier power source connected between a connection point between the transmission line and the switching circuit and an input terminal or an output terminal; ON / OFF based on a predetermined control signal supplied as a bias
An amplifier that operates off to amplify or de-amplify a high-frequency signal on a branch line, wherein the switching circuit of any one of the plurality of branch lines is in a cutoff state, and the amplifier of the same line is A high-frequency switch circuit that is in an amplifying state, has the switching circuits of the remaining branch lines of the plurality of branch lines in a short-circuited state, and has the amplifier in the same line in a non-amplified state.