JP3647712B2 - Phase shifter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a phase shifter that electrically changes the phase of a signal in a microwave band and a millimeter wave band.
[0002]
[Prior art]
FIG. 5 shows a conventional phase shifter shown in, for example, pp. 3-121, 1981 Proceedings of the IEICE General Conference.
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 is a high-frequency equivalent circuit at the time of ON when a forward bias is applied to the semiconductor element 4a and at the time of OFF when a reverse bias is applied, for example. A similar equivalent circuit is formed for the semiconductor element 4b connected to the terminal isolated from the terminal of the hybrid coupler 2 to which the semiconductor element 4a is connected.
[0003]
Next, the operation will be described.
The high-frequency signal input from the input / output terminal 1a is divided into two by the 3 dB hybrid coupler 2 with an equal amplitude and a phase difference of 90 degrees. One of the two high-frequency signals distributed 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.
[0004]
When the semiconductor elements 4a and 4b are ON, the semiconductor elements 4a and 4b can be regarded as a small resistance as shown in FIG. 6A. Therefore, the tips of the matching circuits 3a and 3b are grounded with a small resistance. Yes.
On the other hand, when the semiconductor elements 4a and 4b are OFF, since the semiconductor elements 4a and 4b can be regarded as capacitors as shown in FIG. 6B, the tips of the matching circuits 3a and 3b are grounded via the capacitors. Has been.
By turning on / off the semiconductor elements 4a and 4b, the impedances of the matching circuits 3a and 3b as seen from the hybrid coupler 2 side are different, and the reflection phase is changed.
[0005]
The high-frequency signal reflected by the matching circuits 3a and 3b is input again to the hybrid coupler 2, and the high-frequency signal from the matching circuit 3a and the high-frequency signal from the matching circuit 3b are combined in the hybrid coupler 2 and then input from the input / output terminal 1b. Is output.
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]
[Problems to be solved by the invention]
However, in the conventional phase shifter described above, the loss generated in the semiconductor elements 4a and 4b when the semiconductor elements 4a and 4b are turned on, and the semiconductor elements 4a and 4b when the semiconductor elements 4a and 4b are turned off. Therefore, there is a problem that the amplitude change is large at the time of phase shift switching.
[0007]
The present invention has been made to solve the above-described problems, and an object thereof is to obtain a phase shifter capable of reducing an amplitude change at the time of phase shift switching.
[0008]
[ Means for Solving the Problems ]
The phase shifter according to the present invention includes a hybrid coupler, a first semiconductor element connected to the first terminal of the hybrid coupler, and a second semiconductor element isolated from the first terminal of the hybrid coupler. A phase shifter comprising: a second semiconductor element connected to a terminal; and a third and fourth terminal not connected to the semiconductor element of the hybrid coupler as input / output terminals. it is characterized in that the resistance to the semiconductor element connected in parallel, respectively.
[0009]
Further, a capacitor is connected in series to the resistor, and the series connection body is connected in parallel to the first and second semiconductor elements, respectively.
[0010]
Furthermore, a diode or FET is used as the semiconductor element.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
1 is a block diagram showing a phase shifter according to Embodiment 1 of the present invention.
In FIG. 1, 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, for example, when the forward bias is applied to the semiconductor element 4a and when the reverse bias is applied. A similar equivalent circuit is formed for the semiconductor element 4b and the resistor 5b connected to the terminal isolated from the terminal of the hybrid coupler 2 to which the semiconductor element 4a and the resistor 5a are connected.
[0012]
Next, the operation will be described.
The high-frequency signal input from the input / output terminal 1a is divided into two by the 3 dB hybrid coupler 2 with an equal amplitude and a phase difference of 90 degrees. One of the two distributed high frequency signals is input to the semiconductor element 4a and the resistor 5a via the matching circuit 3a, and the other is input to the semiconductor element 4b and the resistor 5b via the matching circuit 3b.
[0013]
When the semiconductor elements 4a and 4b are ON, the semiconductor elements 4a and 4b can be regarded as a small resistance as shown in FIG. 2A, and therefore, the tips of the matching circuits 3a and 3b have a small equalization resistance and a semiconductor. Grounded by resistors 5a and 5b connected in parallel to the 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 capacitors as shown in FIG. 2B, so that the tips of the matching circuits 3a and 3b are capacitors and the semiconductor elements 4a. 4b is grounded via resistors 5a and 5b connected in parallel.
By turning on / off the semiconductor elements 4a and 4b, the impedances of the matching circuits 3a and 3b as seen from the hybrid coupler 2 side are different, and the reflection phase is changed.
[0014]
The high-frequency signal reflected by the matching circuits 3a and 3b is input again to the hybrid coupler 2, and the high-frequency signal from the matching circuit 3a and the high-frequency signal from the matching circuit 3b are combined in the hybrid coupler 2 and then input from the input / output terminal 1b. Is output.
[0015]
Here, when the semiconductor elements 4a and 4b are turned ON / OFF, the reflection phase of the matching circuits 3a and 3b as seen from the hybrid coupler 2 changes, so that the phase of the high-frequency signal output from the input / output terminal 1b is changed. be able to.
Further, the values of the resistors 5a and 5b are set so that the loss of the phase shifter when the semiconductor elements 4a and 4b are ON and the loss of the phase shifter when the semiconductor elements 4a and 4b are OFF are equal. As a result, it is possible to reduce the loss fluctuation at the time of phase shift switching.
[0016]
Embodiment 2. FIG.
In the first embodiment described above, the resistors 5a and 5b are connected in parallel to the semiconductor elements 4a and 4b so as to reduce the amplitude difference at the time of phase shift switching. When the voltage is high, the current consumption increases due to the current flowing through the resistors 5a and 5b. In this case, an embodiment will be described in which a current difference does not flow through the resistors 5a and 5b, and a loss difference at the time of phase shift switching can be reduced.
[0017]
FIG. 3 is a configuration diagram of the phase shifter in such a case.
In FIG. 3, the same parts as those of the first embodiment shown in FIG. As new symbols, 6a and 6b are capacitors.
[0018]
Here, when the semiconductor elements 4a and 4b are turned ON / OFF, the reflection phase of the matching circuits 3a and 3b as seen from the hybrid coupler 2 changes, so that the phase of the high-frequency signal output from the input / output terminal 1b is changed. be able to. Further, the values of the resistors 5a and 5b are set so that the loss of the phase shifter when the semiconductor elements 4a and 4b are ON and the loss of the phase shifter when the semiconductor elements 4a and 4b are OFF are equal. As a result, 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 the power consumption does not increase.
[0019]
Embodiment 3 FIG.
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 the diodes.
[0020]
FIG. 4 is a configuration diagram according to the third embodiment when an FET is used as a semiconductor element.
In FIG. 4, the same parts as those of the second embodiment shown in FIG. As new symbols, 7a and 7b are FETs used as semiconductor elements, and have the same effects as those of the second embodiment.
[0021]
In each of the above embodiments, the hybrid coupler 2, the matching circuits 3a and 3b, the semiconductor elements 4a and 4b or 7a and 7b, and the resistors 5a and 5b are individually combined. The same effect can be obtained even if a part is integrated on the semiconductor substrate.
[0022]
【The invention's effect】
As described above, according to the present invention, since the resistors are connected in parallel to the respective semiconductor elements, loss variation at the time of phase switching can be reduced, and the change in amplitude can be reduced.
[0023]
In addition, since a series connection body in which a capacitor is connected in series to the resistor is connected in parallel to each semiconductor element, when the bias voltage of each semiconductor element is high, current does not flow through the resistor, The loss difference can be reduced.
[0024]
Furthermore, a phase shifter can be comprised using a diode or FET as the said semiconductor element.
[Brief description of the drawings]
FIG. 1 is a configuration diagram illustrating a phase shifter according to a first embodiment of the present invention.
2 is a high-frequency equivalent circuit diagram of the semiconductor element 4a and the resistor 5a in FIG. 1, for example, when the semiconductor element 4a is turned on when a forward bias is applied and when it is turned off when a reverse bias is applied.
FIG. 3 is a block diagram showing a phase shifter according to Embodiment 2 of the present invention.
FIG. 4 is a block diagram showing a phase shifter according to Embodiment 3 of the present invention.
FIG. 5 is a configuration diagram showing a phase shifter according to a conventional example.
6 is a high-frequency equivalent circuit diagram of the semiconductor element 4a in FIG. 5, for example, when the semiconductor element 4a is turned on when a forward bias is applied and when it is turned off when a reverse bias is applied.
[Explanation of symbols]
1a, 1b Input / output terminal, 2 Hybrid coupler, 3a, 3b Matching circuit, 4a, 4b Semiconductor element (diode), 5a, 5b Resistance, 6a, 6b Capacitor, 7a, 7b Semiconductor element (FET).

Claims (3)

A hybrid coupler,
A first semiconductor element connected to the first terminal of the hybrid coupler;
A second semiconductor element connected to a second terminal that is isolated with respect to the first terminal of the hybrid coupler, and a third and a fourth terminal to which the semiconductor element of the hybrid coupler is not connected In the phase shifter with
A phase shifter comprising resistors connected in parallel to the first and second semiconductor elements, respectively. The phase shifter according to claim 1, wherein a capacitor is connected in series to the resistor, and the series connection body is connected in parallel to the first and second semiconductor elements. The phase shifter according to claim 1 or 2, wherein a diode or an FET is used as the semiconductor element.

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