JPH053418A - Phase shifter - Google Patents

Abstract

PURPOSE:To improve the setting accuracy of a phase shift by selecting any of two radio wave propagation paths each comprising an active inductance element and an active reactance element connecting to a variable capacitor and a variable resistor while varying the bias condition of the elements. CONSTITUTION:An LPF 14 lagging a phase of the circuit is provided with a FET 18a, an active inductor 19 in which a variable resistor 17a and a variable capacitor 16a are connected respectively between a gate and a drain and between the gate and a source of the FET 18a, an active inductor 20 of similar configuration, an active capacitor 21 in which a variable resistor 16a and a variable capacitor 16b are connected respectively between a source and a gate and between the gate and a drain of the FET 18b. An HPF 15 leading the phase is formed similarly, and either of the LPF, HPF 14, 15 is selected in the radio wave transmission line in response to a bias voltage to FETs 18a-18c, 18d-18f to select either the phase lag or the phase lead, and consecutive phase shift is set and the setting accuracy of the phase shift is enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of phase shift amount setting accuracy of a phase shifter.

[0002]

2. Description of the Related Art FIG. W. Suckl
ing, "S-BandPhaseShifter u
Sing Monolithic GaAs Circ
uits "IEEE International S
solid-State Circuit Confer
ence 1982 PP. It is an equivalent circuit diagram which shows an example of the conventional phase shifter shown by 134-135. In the figure, 1 is an input terminal, 2 is an output terminal, 3, 4, 5, and 6 are first, second, third, and fourth switching field-effect transistors (hereinafter abbreviated as switching FETs), 7
Is a first switch F electrically connected to the input terminal 1.
First composed of ET3 and second switching FET4
Single-pole double-throw switch (hereinafter abbreviated as SPDT switch), 8 is a second SPDT switch composed of a third switch FET 5 and a fourth switch FET 6 electrically connected to the output terminal 2. , 9 are F for the first switch
The first inductors 10a and 10b connected in series between the ET3 and the third switching FET 5 have one end connected to the first inductor 9 and the other end grounded. 11 is a second capacitor connected in series between the second switching FET 4 and the fourth switching FET 6, and 12a and 12b have one end connected to the second capacitor 11 and the other end grounded. The second inductors 13a and 13b are the first and second bias terminals, respectively. Here, the first switch FET 3
And the second switching FET 4 and the third switching FET
A bias voltage is applied to the fifth and fourth switching FETs 6 via the first and second bias terminals 13a and 13b, but the details of the bias circuit required at this time are omitted here. There is. In addition, the first inductor 9 and the first
A low-pass filter 14 (hereinafter abbreviated as LPF) is formed by the capacitors 10a and 10b.
The second capacitor 11 and the second inductors 12a, 12
A high-pass filter 15 (hereinafter abbreviated as HPF) is formed with b. In addition, here, LPF, HP
The element values of the respective reactance elements are set such that F has a pass band of a required frequency.

Next, the operation will be described. The conventional phase shifter is configured as described above, and the fact that a phase delay occurs in the pass band of the LPF 14 and a phase lead occurs in the pass band of the HPF 15 is used to set the radio wave propagation path to the LPF 14
The required amount of phase shift is obtained by switching to the HPF 15 side or the HPF 15 side. First, F for the first switch
The bias voltage applied from the first bias terminal 13a to the gates of the ET3 and the third switching FET5 is set to 0V, respectively, and the second bias terminal is connected to the gates of the second switching FET4 and the fourth switching FET6. The case where the bias voltage applied from 13b is the pinch-off voltage will be described. In this case, the drains of the first switching FET 3 and the second switching FET 4
Conduction is established between the sources, and the third switching FET 5
And the drain and source of the fourth switching FET 6 are cut off, so that the electric wave incident from the input terminal 1 is L
By passing through the PF 14, a phase delay occurs and appears at the output terminal 2. Next, when the bias voltage applied to the four switching FETs is reversed from the above, the radio wave propagation path is reversed from that in the above case, and the radio wave incident from the input terminal 1 must pass through the HPF 15. This causes a phase lead and appears at the output terminal 2. Therefore, in the conventional phase shifter, the bias voltage applied to the four switching FETs is switched as described above, and the first SPDT switch 7 and the second SPDT switch 8 are switched so that the input-output terminals are connected to each other. The amount of phase shift can be changed. Here, in addition to the first SPDT switch 7, the second SP
By providing the DT switch 8, the circuit element forming the phase shifter and the external circuit in which the phase shifter is inserted are completely separated from each other so that they can operate without affecting each other. As described above, this type of phase shifter
2 by switching the radio wave propagation path between the HPF15 side and the HPF15 side
The same passing phase difference can be obtained, and the required phase shift amount can be realized by cascade-connecting the phase shifters having different phase shift amounts thus obtained in multiple stages.

[0004]

The conventional microwave semiconductor phase shifter is constructed as described above, and the LPF, HP
To realize F, an inductor and a capacitor are needed. Conventionally, as shown in the above-mentioned document, such an element has been constituted by a passive element such as a spiral inductor or an MIM capacitor. Therefore, when a phase shifter of this kind is realized by a monolithic circuit technology suitable for mass production, it is difficult to keep the element values of the above passive elements constant due to manufacturing problems, and the values vary. .. As a result, the passing phase of the LPF and HPF changes from the design value, and there arises a problem that the required phase shift amount cannot be obtained. further,
In the conventional microwave semiconductor phase shifter, it is not possible to obtain a continuous change in the amount of phase shift with a single-stage phase shifter, so it is necessary to have a multi-stage configuration in order to set the required amount of phase shift accurately. ,
It was causing an increase in cost and size.

The present invention has been made in order to solve the above problems, and switches the phase delay and the phase lead while maintaining the required number of active elements equal to that of the conventional phase shifter, and
An object of the present invention is to obtain a phase shifter with a high phase shift amount setting accuracy that allows continuous setting of the phase shift amount.

[0006]

An input terminal, an output terminal, an active element such as a transistor or a field effect transistor, a resistor, and a capacitor, which are connected between the input terminal and the output terminal. A reactance active element such as a reactance transistor or a reactance field effect transistor, having a low-pass filter configured with an active inductor or an active capacitor formed so as to make the reactance variable by varying the resistance or the capacitor. A first radio wave propagation path and a second radio wave propagation path having a high-pass filter configured by including the active inductor or the active capacitor are provided, and the first radio wave propagation path and the second radio wave propagation path. At least one of an active inductor and an active capacitor included in each of the There the arranged input terminal end, the active inductor or the first radio wave propagation path and the second by varying the applied bias condition to the active capacitor
One of the radio wave propagation paths is selected.

[0007]

In the phase shifter constructed as described above, at least one of the active inductors or active capacitors of the first radio wave propagation path and the second radio wave propagation path is arranged at the input terminal end. , One of the radio wave propagation paths is selected by changing the bias condition applied to each active element of the active inductor or active capacitor, and the low-pass filter and the high-pass filter use a variable resistance or capacitor for reactance. Since it is configured to include an active inductor or active capacitor formed so as to be variable, it is possible to continuously set a phase shift amount that gives a phase delay or a phase lead in the selected radio wave propagation path.

[0008]

EXAMPLES Example 1. FIG. 1 is a circuit configuration diagram showing an embodiment of the phase shifter of the present invention. In this embodiment, a microwave semiconductor phase shifter similar to that of the conventional example will be described using a reactance field effect transistor (hereinafter, referred to as reactance FET). In the figure, 16a to 16f are variable capacitors, and 17a to 17f.
Is a variable register, 18a to 18f are field effect transistors (hereinafter abbreviated as FETs), and 19 and 20 are variable capacitors 16a and 16c, which are FETs 18a and 18c, respectively.
Of the variable resistors 17a and 17c between the gates and drains of the FETs 18a and 18c, respectively, and the first and second active inductors 21, and the variable resistor 17b between the gates and sources of the FETs 18a and 18c. The variable capacitor 16b is a first active capacitor provided between the gate and drain of the FETs 18a and 18c, 22
Is a third structure having the same configuration as the first and second active inductors.
The active inductors 23 and 24 are second and third active capacitors having the same configuration as the first active capacitor 21. Here, the first and second active inductors 19, 2
0 and the first active capacitor 21 form a T-shaped LPF 14 between the input terminal 1 and the output terminal 2, and the third active inductor 22 and the second and third active capacitors 23, 2
The T-shaped HPF1 between the input terminal 1 and the output terminal 2
5 are configured. Each FET has first, second, third and fourth gate bias terminals 25, 26, 2
The gate bias voltage is applied from 7 and 28. Here, although it is necessary to apply the drain bias voltage to the FETs 18a to 18f, details of the gate bias circuit and illustration of the drain bias circuit are omitted here.

FIG. 2 is a circuit diagram for explaining a circuit configuration for realizing an inductor and a capacitor in a reactance FET. With such a circuit configuration, it is possible to realize a reactance element by using a three-terminal active element such as a transistor or an FET. 196-198. By changing the values of the variable resistor 17 and the variable capacitor 16 connected to the gate, the inductance value and the capacitance value obtained by these circuits can be changed. Therefore, the LPF 14 and the HPF 15 configured by using such a circuit can change the passing phase without deteriorating the performance thereof.

Next, the operation of the phase shifter will be described. Here, a bias is applied to the first and second gate bias terminals 25 and 26 so that the first and second active inductors 19 and 20 and the first active capacitor 21 function. On the other hand, a pinch-off voltage is applied to the third gate bias terminal 27, and the FET 18d and the FET 18f
FET drain voltage is 0V
And the drain and source of each of the FET 18f are cut off. Further, when the fourth gate bias terminal 28 is set to 0V and the drain bias voltage of the FET 18e is set to 0V, the drain and source of the FET 18e are short-circuited. As a result, the path on the HPF 15 side is cut off, and all the radio waves incident from the input terminal 1 pass through the LPF 14, causing a phase delay and appearing at the output terminal 2. Then, the first and second gate bias terminals 25, 2
6 applied bias and third and fourth gate bias terminals 2
By reversing the applied bias of 7 and 28 and changing the drain bias voltage condition accordingly, the propagation path of the radio wave can be switched to the HPF 15 side, and the input terminal 1
All the radio waves incident from will pass through the HPF 15 and will appear in the output terminal 2 with a phase lead.

As described above, the radio wave propagation path can be switched between the LPF 14 side and the HPF 15 side according to the applied bias voltage condition, and the values of the inductor and the capacitor forming the LPF 14 and HPF 15 can be controlled. Therefore, it is possible to continuously set an arbitrary amount of phase shift over a relatively wide range from the phase delay to the phase advance by the one-stage phase shifter.

Example 2. FIG. 3 is a circuit diagram showing another embodiment of the phase shifter of the present invention. In the first embodiment, the HPF 14 and the LPF 15 each have a configuration in which three reactance FETs are used in the filter, but in this embodiment, five reactances F are used.
The structure of the microwave semiconductor phase shifter when the HPF 14 and the LPF 15 are formed by using ET is shown. In the figure, 1
6g to 16j are variable capacitors, 17g to 17j are variable resistors, 18g to 18j are FETs, 29 is a fourth active capacitor, 30 is a fourth active inductor, and 31 is a fifth.
, And 32 is a fifth active capacitor. The configurations of the respective active capacitors and active inductors are the same as in FIG. The HPF 14 is formed by the first, second and fourth active inductors 19, 20, 30 and the first and fourth active capacitors 21, 29, and the second, third, fifth active capacitors 23, 24 are formed. , 32 and the third and fifth active inductors 22, 31 form the LPF 15.

Here, the operation of the reactance FET and the phase shifter is the same as that of the first embodiment, and the description thereof will be omitted.

According to this embodiment, in addition to the effect similar to that of the first embodiment, there is an advantage that the band can be broadened by the multistage structure of the filter composed of the capacitor and the inductor.

By the way, in the above-mentioned first and second embodiments, the case where the HPF 14 and the LPF 15 are respectively constituted by using three or five reactance FETs constituting the active capacitor or the active inductor has been described.
The number of reactance FETs used is not limited to this, and at least one may be arranged at the end on the input terminal 1 side, and the number of reactance FETs forming the HPF 14 and the LPF 15 may not be the same. Incidentally, the reactance FET may be any one as long as at least one arranged at the end on the side of the input terminal 1 is formed so as to make the reactance variable by changing the resistance or the capacitor, and all the capacitors and the inductors are formed. It need not be variable.

In the first and second embodiments, the case where the active capacitor and the active inductor are formed by the reactance FET having the basic structure shown in FIG. 2 has been described. Alternatively, a resistance or reactance element may be added.

In the first and second embodiments described above,
Reactance F using an FET as an active element with 3 terminals
Although the case of ET is shown, the present invention is not limited to this, and a bipolar transistor or HEMT, for example, can be used for the same configuration.

[0018]

As described above, according to the present invention, the first radio wave propagation path having the low-pass filter configured with the active inductor or the active capacitor formed so as to make the reactance variable, , A second radio wave propagation path having a high-pass filter, and one of the first radio wave propagation path and the second radio wave propagation path is selected by changing a bias condition applied to the active inductor or the active capacitor. Therefore, there is an effect that the required number of active elements is made equal to that of the conventional phase shifter, the phase delay and the phase lead are switched, and the continuous phase shift amount can be set.

[Brief description of drawings]

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

FIG. 2 is a circuit diagram for explaining a circuit configuration for realizing an active inductor and an active capacitor in the reactance FET according to the first embodiment of the present invention.

FIG. 3 is a circuit configuration diagram showing a second embodiment of the present invention.

FIG. 4 is an equivalent circuit diagram showing a conventional phase shifter.

[Explanation of symbols]

 1 Input Terminal 2 Output Terminal 3 First Switch Field Effect Transistor 4 Second Switch Field Effect Transistor 5 Third Switch Field Effect Transistor 6 Fourth Switch Field Effect Transistor 7 First Single Pole Double Throw Switch 8 Second Single Pole Double Throw Switch 9 First Inductor 10 First Capacitor 11 Second Capacitor 12 Second Inductor 13 Bias Terminal 14 Low Pass Filter 15 High Pass Filter 16 Variable Capacitor 17 Variable Resistor 18 Field effect transistor 19 First active inductor 20 Second active inductor 21 First active capacitor 22 Third active inductor 23 Second active capacitor 24 Third active capacitor 25 First gate bias terminal 26th 2 Gate bias terminal 27 3rd game Gate bias terminal 29 of the bias terminal 28 fourth fourth active capacitor 30 fourth active inductor 31 fifth active inductor 32 fifth active capacitor

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[Procedure amendment]

[Submission date] May 12, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction content]

By the way, in the above-mentioned first and second embodiments, the case where the HPF 14 and the LPF 15 are respectively constituted by using three or five reactance FETs constituting the active capacitor or the active inductor has been described.
The number of reactance FETs used is not limited to this, and at least one may be arranged at the end on the input terminal 1 side, and the number of reactance FETs forming the HPF 14 and the LPF 15 may not be the same. The reactance FET may be any one as long as at least one of the reactance FETs arranged at the end on the input terminal 1 side is formed so that the reactance can be changed by changing the resistance or the capacitor, and the LPF 14 and the HPF 15 are configured. Not all capacitors and inductors need to be variable.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenji Ito 5-1-1 Ofuna, Kamakura-shi Electronic Systems Research Center, Mitsubishi Electric Corporation

Claims (1)

Claim: What is claimed is: 1. An input terminal, an output terminal, an active element such as a transistor or a field effect transistor, a resistor and a capacitor, which are connected between the input terminal and the output terminal. A low-pass filter configured by a reactance active element such as a configured reactance transistor or a reactance field effect transistor, which is provided with an active inductor or active capacitor formed so as to make the reactance variable by varying the resistance or the capacitor. And a second radio wave propagation path having a high-pass filter configured by including the active inductor or the active capacitor, and the first radio wave propagation path and the second radio wave. At least the active inductor or active capacitor in each of the propagation paths One is arranged at the input terminal end, and one of the first radio wave propagation path and the second radio wave propagation path is selected by changing the bias condition applied to the active inductor or the active capacitor. ..