JP2001284904A - Phase shifter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phase shifter capable of reducing amplitude change at the time of phase shift switching, concerning the phase shifter, which is composed of a hybrid coupler, a first semiconductor device connected to the first terminal of the hybrid coupler and a second semiconductor device connected to the second terminal to be isolated from the first terminal of the hybrid coupler, making third and fourth terminals, to which the semiconductor device is not connected, of the hybrid coupler into input and output terminals. SOLUTION: Resistors 5a and 5b are respectively parallel connected to first and second semiconductor devices 4a and 4b and when the semiconductor devices are turned on and off, the loss is made equal. Otherwise, a capacitor is serially connected to the resistor and the relevant serially connected body is respectively parallel connected to the respective semiconductor devices. Further, a diode or FET is used as a semiconductor device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a microwave band,
The present invention relates to a phase shifter that electrically changes the phase of a signal in a millimeter wave band.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional phase shifter disclosed in, for example, Proceedings of the IEICE General Conference, 1979, pp. 3-121. In FIG. 5, 1a and 1b are input / output terminals, 2 is a hybrid coupler, 3a and 3b are matching circuits, and 4a and 4b are semiconductor elements. FIG. 6 shows, for example, the semiconductor element 4
4A is a high-frequency equivalent circuit when ON is applied with a forward bias and OFF when a reverse bias is applied to a. Note that a similar equivalent circuit is formed for the semiconductor element 4b connected to a terminal that is isolated from the terminal of the hybrid coupler 2 to which the semiconductor element 4a is connected.

Next, the operation will be described. I / O terminal 1
The high-frequency signal input from a is divided into two signals by the 3 dB hybrid coupler 2 with equal amplitude and a phase difference of 90 degrees. One of the two divided high-frequency signals is input to the semiconductor element 4a via the matching circuit 3a, and the other high-frequency signal is input to the semiconductor element 4b via the matching circuit 3b.

When the semiconductor elements 4a and 4b are ON, the semiconductor elements 4a and 4b can be regarded as having a small resistance as shown in FIG. 6A, so that the tips of the matching circuits 3a and 3b have a small resistance. Grounded. On the other hand, when the semiconductor elements 4a and 4b are OFF, the semiconductor elements 4a and 4b
As shown in FIG. 6B, the matching circuits 3a and 3b are grounded via capacitors because they can be regarded as capacitors. By turning on / off the semiconductor elements 4a and 4b, the impedances of the matching circuits 3a and 3b viewed from the hybrid coupler 2 side differ, and the reflection phase changes.

The high-frequency signals reflected by the matching circuits 3a and 3b are input to the hybrid coupler 2 again, where the high-frequency signal from the matching circuit 3a and the high-frequency signal from the matching circuit 3b are combined and input / output. Terminal 1b
Output from Thus, by turning on / off the semiconductor elements 4a and 4b, the phase of the high-frequency signal output from the input / output terminal 1b can be changed.

[0006]

However, in the conventional phase shifter described above, the semiconductor elements 4a and 4b are
Since the loss that occurs in the semiconductor elements 4a and 4b when N is different from the loss that occurs in the semiconductor elements 4a and 4b when the semiconductor elements 4a and 4b are turned off, the amplitude change is large at the time of phase shift switching. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to obtain a phase shifter capable of reducing an amplitude change at the time of phase shift switching.

[0008] A phase shifter according to the present invention is isolated from a hybrid coupler, a first semiconductor element connected to a first terminal of the hybrid coupler, and a first terminal of the hybrid coupler. A second semiconductor device connected to a second terminal, wherein the semiconductor device of the hybrid coupler is not connected to the third and fourth terminals as an input / output terminal, the phase shifter, wherein the first and the A resistor is connected in parallel to the second semiconductor element, and the loss when the semiconductor element is turned on / off is equalized.

Further, a capacitor is connected in series to the resistor, and the series-connected body is connected in parallel to the first and second semiconductor elements, respectively.

Further, the invention is characterized in that a diode or an FET is used as the semiconductor element.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a configuration diagram showing a phase shifter according to Embodiment 1 of the present invention. FIG.
, 1a and 1b are input / output terminals, 2 is a hybrid coupler, 3a and 3b are matching circuits, 4a and 4b are semiconductor elements, and 5a and 5b are resistors. FIG. 2 is a high-frequency equivalent circuit diagram of the semiconductor element 4a and the resistor 5a when the semiconductor element 4a is ON when a forward bias is applied and when the semiconductor element 4a is OFF when a reverse bias is applied. Note that the semiconductor element 4a and the resistor 5
The semiconductor device 4b and the resistor 5b connected to the terminal isolated from the terminal of the hybrid coupler 2 to which a is connected form a similar equivalent circuit.

Next, the operation will be described. I / O terminal 1
The high-frequency signal input from a is divided into two signals by the 3 dB hybrid coupler 2 with equal amplitude and a phase difference of 90 degrees. One of the two divided high-frequency signals is input to the semiconductor element 4a and the resistor 5a via the matching circuit 3a, and the other is supplied to the matching circuit 3b.
Is input to the semiconductor element 4b and the resistor 5b via the.

When the semiconductor elements 4a and 4b are ON, the semiconductor elements 4a and 4b can be regarded as having a small resistance as shown in FIG. 2A. It is grounded by a resistor and resistors 5a and 5b connected in parallel to the semiconductor elements 4a and 4b. On the other hand, when the semiconductor elements 4a and 4b are OFF, the semiconductor elements 4a and 4b
Can be regarded as a capacitance, as shown in FIG. 2 (b). Therefore, the tips of the matching circuits 3a and 3b are grounded via capacitors and resistors 5a and 5b connected in parallel to the semiconductor elements 4a and 4b. . ON / OF the semiconductor elements 4a and 4b
By performing F, the impedances of the matching circuits 3a and 3b viewed from the hybrid coupler 2 side differ, and the reflection phase changes.

The high-frequency signals reflected by the matching circuits 3a and 3b are input again to the hybrid coupler 2, where the high-frequency signal from the matching circuit 3a and the high-frequency signal from the matching circuit 3b are combined and input and output. Terminal 1b
Output from

Here, the semiconductor elements 4a and 4b are turned on / off.
When the FF is performed, since the reflection phases of the matching circuits 3a and 3b as viewed from the hybrid coupler 2 change, the phase of the high-frequency signal output from the input / output terminal 1b can be changed. Also, the resistors 5a, 5b are set so that the loss of the phase shifter when the semiconductor elements 4a, 4b are ON and the loss of the phase shifter when the semiconductor elements 4a, 4b are OFF are equal.
By setting the value, it is possible to reduce the loss fluctuation at the time of phase shift switching.

Embodiment 2 In the first embodiment, the resistors 5a and 5b are connected in parallel to the semiconductor elements 4a and 4b to reduce the amplitude difference at the time of phase shift switching. When the voltage is high, current consumption increases due to current flowing through the resistors 5a and 5b. In such a case, the resistors 5a, 5
An embodiment will be described in which a current can be prevented from flowing through b to reduce a loss difference at the time of phase shift switching.

FIG. 3 is a configuration diagram of the phase shifter in such a case. 3, the same parts as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted. As new symbols, 6a and 6b are capacitors.

Here, the semiconductor elements 4a and 4b are turned ON / O.
When the FF is performed, since the reflection phases of the matching circuits 3a and 3b as viewed from the hybrid coupler 2 change, the phase of the high-frequency signal output from the input / output terminal 1b can be changed. Also, the resistors 5a, 5b are set so that the loss of the phase shifter when the semiconductor elements 4a, 4b are ON and the loss of the phase shifter when the semiconductor elements 4a, 4b are OFF are equal.
By setting the value, it is possible to reduce the loss fluctuation at the time of phase shift switching. Further, since the capacitors 6a and 6b are connected in series with the resistors 5a and 5b, no current flows through the resistors 5a and 5b, and power consumption does not increase.

Embodiment 3 In the first and second embodiments described above, diodes are used as the semiconductor elements 4a and 4b. However, similar effects can be obtained by using semiconductor elements other than diodes.

FIG. 4 is a configuration diagram according to a third embodiment in which an FET is used as a semiconductor element. 4, the same components as those of the second embodiment shown in FIG. 3 are denoted by the same reference numerals, and the description thereof will be omitted. As new codes, 7a, 7
b is an FET used as a semiconductor element, and has the same effect as in the second embodiment.

In each of the above embodiments, the hybrid coupler 2, the matching circuits 3a and 3b, the semiconductor elements 4a and 4
Although an example in which b or 7a, 7b and resistors 5a, 5b are individually combined is described, the same effect can be obtained by integrally forming all or a part of the above on a semiconductor substrate.

[0022]

As described above, according to the present invention, a resistor is connected in parallel to each semiconductor element, and the loss when each semiconductor element is turned ON / OFF is made equal, so that the phase shift switching is performed. The loss fluctuation at the time can be reduced, and the amplitude change can be reduced.

In addition, since a series connection body in which a capacitor is connected in series with the resistor is connected in parallel to each semiconductor element, when a bias voltage of each semiconductor element is high, current does not flow through the resistor, and phase shift is performed. The loss difference at the time of switching can be reduced.

Further, a phase shifter can be constituted by using a diode or an FET as the semiconductor element.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a phase shifter according to Embodiment 1 of the present invention.

FIG. 2 is a high-frequency equivalent circuit diagram of the semiconductor element 4a and the resistor 5a in FIG. 1 when the semiconductor element 4a is ON when a forward bias is applied and when the reverse bias is applied OFF.

FIG. 3 is a configuration diagram showing a phase shifter according to Embodiment 2 of the present invention.

FIG. 4 is a configuration diagram showing a phase shifter according to Embodiment 3 of the present invention.

FIG. 5 is a configuration diagram illustrating a phase shifter according to a conventional example.

6 is a high-frequency equivalent circuit diagram of the semiconductor element 4a shown in FIG. 5, for example, when the semiconductor element 4a is ON when a forward bias is applied, and when the semiconductor element 4a is OFF when a reverse bias is applied.

[Explanation of symbols]

1a, 1b input / output terminal, 2 hybrid coupler, 3
a, 3b matching circuit, 4a, 4b semiconductor element (diode), 5a, 5b resistor, 6a, 6b capacitor,
7a, 7b Semiconductor element (FET).

Continuing on the front page (72) Inventor Kazuhiko Nakahara 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Inventor Nao Takagi 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Co., Ltd. F term in the company (reference) 5J012 HA05

Claims (3)

[Claims] 1. A hybrid coupler, a first semiconductor element connected to a first terminal of the hybrid coupler, and a second terminal isolated from the first terminal of the hybrid coupler. A phase shifter having third and fourth terminals, to which the semiconductor element of the hybrid coupler is not connected, as input / output terminals, wherein the first and second semiconductor elements have a resistance. Are connected in parallel, and the loss when the semiconductor element is turned ON / OFF is equalized. 2. The phase shifter according to claim 1, wherein a capacitor is connected in series to the resistor, and the series connection is connected in parallel to the first and second semiconductor elements, respectively. 3. The phase shifter according to claim 1, wherein a diode or a FET is used as the semiconductor element.