JP2003264403A - Micro wave phase shifter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a micro wave phase shifter with small fluctuation of loss even when a phase is changed. <P>SOLUTION: Inductance elements are connected with variable capacitance elements constituting the micro wave phase shifter in series respectively and resistors are connected between a pass terminal of 90° hybrid and a ground, and between a coupling terminal and the ground respectively. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave phase shifter used in a microwave band radar or a communication device and compensating for a phase change of these devices with respect to temperature.

[0002]

2. Description of the Related Art In a microwave radar device or a communication device, an active phased array antenna composed of a large number of element antennas is used as an antenna therefor from the viewpoint of reliability and high speed. A transmitting module or a receiving module for amplifying or controlling a signal is used for the antenna. When a large number of these modules are arranged, it is difficult to control the heat of each module, and a temperature distribution generally occurs in each module.

Therefore, in each module, it is desirable that the amplitude and the phase do not change much with respect to the temperature, and an attenuator and a phase shifter for compensating the temperature characteristic are used for that. In particular, it relates to a phase shifter for performing phase compensation here.

FIG. 13 shows, for example, MICROWAVE JOURNAL 1989 S.
It shows the structure of the conventional phase shifter shown in TATE OF ART REFERENCE pp109, where 1 is a 90 ° hybrid,
Reference numeral 2 is an input terminal, 3 is an isolation terminal, 4 is a coupling terminal, 5 is a pass terminal, 6 is a variable capacitance element, 7 is a choke circuit, and 8 is a DC power supply.

In this phase shifter, a variable capacitance element 6 is provided between the coupling terminal 4 of the 90 ° hybrid 1 having four terminals and the ground, and between the passage terminal 5 and the ground, and each variable capacitance element 6 has a desired capacitance. A DC power source 8 is connected to each variable capacitance element 6 via a choke circuit 7 in order to apply a bias.

Further, as the 90 ° hybrid 1, a branch line coupler, an interdigital coupler, or the like, which is distributed to the coupling terminal 4 and the passing terminal 5 with the same amplitude and whose phase difference differs by 90 degrees, is used.

A varactor diode, a FET, etc. are used as the variable capacitance element 6, and the case of a varactor diode is shown here. Generally, a varactor diode consists of an inductor Ld, a series resistor Ri, and a junction capacitor caused by a bonding wire as shown in this figure.
It is represented by a series circuit with Cj. The junction capacitor Cj depends on the voltage VR of the DC power supply 8, and the higher the VR, the smaller the Cj.

Further, the choke circuit 7 is designed to have a high impedance in a desired frequency band so as not to affect the microwave characteristics as much as possible. A desired voltage VR can be applied to the variable capacitance element 6.

Next, the operation will be described. The microwave signal input from the input terminal 2 is distributed by the 90 ° hybrid 1 to the coupling terminal 4 and the passing terminal 5 with the same amplitude and a 90 ° phase difference. The distributed microwave signals are supplied to the variable capacitance elements 6, respectively. The supplied microwave signals are 90 ° hybrid 1 by the variable capacitance element 6.
Reflected to the side.

Further, the respective reflected microwave signals are reverse-phase combined at the input terminal 2 and the isolation terminal 3
Since it is in-phase synthesis, all isolation terminals 3
Is output to.

FIG. 14 shows an example of the impedance Za locus on the side of the variable capacitance element 6 shown in FIG. 13 on a Smith chart. Here, the angular frequency ω is kept constant, and the voltage VR applied to the variable capacitance element 6 is changed to VR1, VR0, VR2,
Moreover, the case is shown in which the standardized impedance Z0 (normally 50Ω) is standardized. In general, when the frequency is low, the influence of the inductor Ld due to the bonding wire is small, so that the impedance of the variable capacitance element 6 exhibits capacitance as shown in this figure.

Further, as shown in this figure, VR is changed from VR1 to VR.
By increasing the value to 2, the coupling capacitor Cj of the variable capacitance element 6 gradually decreases, so that Za changes counterclockwise on the line where the resistance component is constant.

Further, the absolute value of the reflection coefficient in the variable capacitance element 6 is determined by the distance from the center of the Smith chart,
The higher the VR, the larger the absolute value of the reflection coefficient at the variable capacitance element 6, and the phase advances. The loss of this type of microwave phase shifter is inversely proportional to the absolute value of the reflection coefficient, and the larger the absolute value, the smaller the loss.

Therefore, in the conventional microwave phase shifter, as shown in FIG.
As shown in Fig. 5, the higher the VR, the more the phase advances (Fig. 15).
(A)), and the characteristic that the loss fluctuates (Fig. 15 (b))
Indicates.

Generally, the phases of the amplifiers, attenuators, etc. which constitute the module are delayed as the temperature rises. Therefore, by mounting this microwave phase shifter on a module and changing the DC voltage VR according to the temperature fluctuation of the phase of the module, the phase fluctuation of the module can be canceled, and the phase fluctuation of the temperature You can get a small module.

[0016]

In the conventional microwave phase shifter, by controlling the voltage VR applied to the variable capacitance element 6, it is possible to suppress the phase fluctuation with respect to the temperature of the module. However, since the loss also changes at the same time, there is a problem in that the module amplitude changes and a high antenna gain cannot be obtained. In order to avoid this, it is necessary to perform the amplitude control in consideration of the loss variation of the microwave phase shifter, and there is a problem that the amplitude control becomes complicated.

The present invention has been made to solve the above problems, and an object thereof is to obtain a microwave phase shifter having a small loss variation even if the phase is changed.

[0018]

A microwave phase shifter according to a first aspect of the present invention includes an inductive element connected in series to a variable capacitance element, and a 90 ° hybrid between a coupling terminal and a ground and between a passing terminal and a ground. The resistors are connected to each.

In the microwave phase shifter according to the second aspect of the present invention, the capacitive element is connected in series to the variable capacitance element, and the resistance is provided between the coupling terminal and the ground of the 90 ° hybrid and between the pass terminal and the ground. It is connected.

The microwave phase shifter according to the third invention is 90
A series circuit of a resistance and a transmission line having a quarter wavelength at a desired frequency and an inductive element is connected between the hybrid coupling terminal and the variable capacitance element and between the passing terminal and the variable capacitance element, respectively.

The microwave phase shifter according to the fourth invention is 90
A series circuit of a resistance and a transmission line having a quarter wavelength at a desired frequency and a capacitive element is connected between the hybrid coupling terminal and the variable capacitance element and between the pass terminal and the variable capacitance element, respectively.

The microwave phase shifter according to the fifth aspect of the present invention is the first aspect.
In the microwave phase shifter of the fourth invention, a 90 ° hybrid input terminal and an isolation terminal are respectively connected with open-end stubs.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. FIG. 1 shows the structure of the microwave phase shifter of the first embodiment, 9 is an inductive element, 10 is a resistor, and 1 to 8 are the same as those in FIG. 13 of the conventional description.

This microwave phase shifter is provided between the coupling terminal 4 and the variable capacitance element 6 and between the passing terminal 5 and the variable capacitance element 6 of the 90 ° hybrid 1 of the conventional microwave phase shifter shown in FIG. The inductive element 9 is provided so as to be connected in series to the variable capacitance element 6, and the 90 ° hybrid 1 is also provided.
A resistor 10 is provided between the coupling terminal 4 and the ground and between the passing terminal 5 and the ground.

FIG. 2 shows the impedance Za of only the variable capacitance element 6 shown in FIG. 1, the impedance Zb of the variable capacitance element 6 as seen through the inductive element 9 and the impedance Za as seen through the inductive element 9 and the resistor 10. Impedance Z of variable capacitance element 6
It is an example in which each c locus is represented on a Smith chart. Here, similar to FIG. 14, the angular frequency ω is kept constant and the applied voltage VR is changed from VR1 to VR2.

The inductive element 9 is for moving the impedance Za of the variable capacitance element 6 in the clockwise direction on a line having a constant resistance component, and is an intermediate voltage VR between the applied voltages VR1 and VR2.
At 0, the value is selected so as to move on the real axis of the Smith chart. Therefore, the impedance of the variable capacitance element 6 viewed through the inductive element 9 moves from Za to Zb.

The impedance Zb of the variable capacitance element 6 viewed through the inductive element 9 has only a real part in the applied voltage VR0 and has the same real part as VR0 in VR1 and VR2, and includes an imaginary part. Therefore, compared to when VR0 is applied, VR1 and VR
Zb at the time of applying 2 becomes high. That is, compared to when VR0 is applied, VR1
And the absolute value of the reflection coefficient when VR2 is applied is large.

Further, by connecting the resistor 10, the impedance Zc of the variable capacitance element 6 seen through the inductive element 9 and the resistor 10 becomes a parallel circuit of Zb and the resistor 10. Therefore, Zc when VR0 is applied has a slightly smaller real part than Zb, and Zc when VR1 and VR2 are applied is almost the same as the real part of Zb, and only the imaginary part is slightly smaller. Therefore, Zb moves to Zc as shown in this figure.

That is, the resistor 10 acts to increase the absolute value of the reflection coefficient of Zb when VR0 is applied and to decrease the absolute value of the reflection coefficient of Zb when VR1 and VR2 are applied. The resistance 10 is selected to be about several hundred Ω in order to reduce loss variation and reduce loss by the applied voltage VR of the microwave phase shifter.

By selecting such a resistor 10, the variable capacitance element 6 seen through the inductive element 9 and the resistor 10 is selected.
The absolute value of the reflection coefficient of is almost constant regardless of the applied voltage VR.

Therefore, as shown in FIG. 3, in this microwave phase shifter, it is possible to obtain the characteristic that the loss is substantially constant with respect to the applied voltage VR and only the phase changes. In addition, resistance 1
By connecting 0, the change of the imaginary part of Zc with respect to VR becomes slightly smaller and the phase change also becomes smaller, but it is practically problematic by selecting the variable capacitance element 6 in which the junction capacitance Cj greatly changes with respect to VR. There is no.

As described above, in the microwave phase shifter of the present invention, the loss is almost constant and only the phase can be changed. Therefore, by applying this to the temperature compensation of the phase of the active phased array antenna module, ,
A high antenna gain can be obtained. Further, there is also an advantage that the amplitude control is not necessary because the amplitude control considering the loss variation of the microwave phase shifter is not necessary.

FIG. 4 is a diagram showing the configuration of another example of the microwave phase shifter of the first embodiment, 1 to 8 are the same as those in FIG. 13 of the conventional description, and 9 and 10 are the same. It is the same as the description of 1.

FIG. 1 shows the case where the inductive element 9 is provided between the coupling terminal 4 and the variable capacitance element 6 and between the passing terminal 5 and the variable capacitance element 6 of the 90 ° hybrid 1, but as shown in FIG. The same applies when the inductive element 9 is provided between the variable capacitance element 6 and the ground.

Embodiment 2. FIG. 5 shows the structure of the microwave phase shifter of the second embodiment, 11 is a capacitive element, 1 to 8 are the same as those in FIG.
0 is the same as the description of FIG.

This microwave phase shifter has the same basic configuration as that of the first embodiment except that the capacitive element 11 is used instead of the inductive element 9 shown in the first embodiment. In general, when the frequency of the variable capacitance element 6 is low, the influence of the inductor Ld due to the bonding wire of the variable capacitance element 6 is small, so that the impedance Za of the variable capacitance element 6 is capacitive as shown in the first embodiment. .

However, in a high frequency band where the influence of the inductor Ld is large, the impedance Za of the variable capacitance element 6 may exhibit inductive properties. In the second embodiment, the variable capacitance element 6 having the inductive impedance Za is used and the applied voltage is
This is to obtain a microwave phase shifter with a small loss variation with respect to VR.

FIG. 6 shows the impedance Za of the variable capacitance element 6 according to the second embodiment of the present invention, the impedance Zb of the variable capacitance element 6 as seen through the capacitive element 11, and the impedance Za of the variable capacitance element 6 as seen through the capacitive element 11 and the resistor 10. 3 is an example in which the loci of the impedance Zc of the variable capacitance element 6 are represented on the Smith chart. Here, as in the first embodiment, the angular frequency ω is kept constant and the applied voltage VR is changed from VR1 to VR2.

The capacitive element 11 is for moving the impedance Za of the variable capacitive element 6 in the counterclockwise direction on the line where the resistance component is constant, and the voltage VR0 intermediate between the applied voltages VR1 and VR2 is used to realize the Smith chart. The value is chosen so that it moves on the axis. Therefore, the impedance of the variable capacitance element 6 viewed through the capacitive element 11 moves from Za to Zb.

Further, the impedance Zb of the variable capacitance element 6 viewed through the capacitive element 11 is higher when VR1 and VR2 are applied than when VR0 is applied, as shown in the first embodiment. Further, by connecting the resistor 10 in parallel, the absolute value of the reflection coefficient of the impedance Zc of the variable capacitance element 6 seen through the capacitive element 11 and the resistor 10 can be made substantially constant.

As described above, the impedance Za of the variable capacitance element 6 can be applied in a high frequency band where it is inductive, the capacitive element 11 is connected in series to the variable capacitance element 6, and the coupling terminal 4 of the 90 ° hybrid 1 is connected. By providing the resistors 10 between the ground and between the passage terminal 5 and the ground, a microwave phase shifter with small loss fluctuation can be obtained.

Since the capacitive element 11 can also be used as a DC blocking capacitor, it is not necessary to newly provide a DC blocking capacitor, and the cost can be reduced as compared with the first embodiment.

Embodiment 3. FIG. 7 shows the structure of the microwave phase shifter according to the third embodiment of the present invention.
Is a transmission line, 1 to 8 are the same as those in FIG. 13 of the conventional description, and 9 and 10 are the same as those in FIG.

This microwave phase shifter is provided between the coupling terminal 4 and the variable capacitance element 6 of the 90 ° hybrid 1 and the passing terminal 5.
A resistor 10 and a series circuit of a transmission line 12 having a quarter wavelength at a desired frequency and an inductive element 9 are connected between the variable capacitance element 6 and the variable capacitance element 6, respectively.

FIG. 8 shows the variable capacitance element 6 seen from the impedance Za of the variable capacitance element 6 shown in FIG. 7 and the inductive element 9.
Locus of impedance Zb of variable capacitance element 6 seen through inductive element 9 and transmission line 12 and impedance Zd of variable capacitance element 6 seen through inductive element 9, transmission line 12 and resistor 10 Is an example in which each is represented on the Smith chart. Here, as in the first and second embodiments, the angular frequency ω is constant and the applied voltage VR is
The figure shows the case of changing from VR1 to VR2.

The inductive element 9 is for converting the impedance Za of the variable capacitance element 6 on the real axis of the Smith chart as shown in the first embodiment.
The impedance of the variable capacitance element 6 viewed through the inductive element 9 moves from Za to Zb. Further, the transmission line 12 has a function of performing impedance conversion of Zb to a high impedance, and the impedance of the variable capacitance element 6 viewed through the transmission line 12 moves from Zb to Zc.

When the characteristic impedance of the transmission line 12 is selected as the standardized impedance Z0 (normally 50Ω), impedance conversion can be performed while maintaining the absolute value of the reflection coefficient of Zb when VR0, VR1 and VR2 are applied. . That is, the absolute value of the reflection coefficient of Zc when VR1 and VR2 are applied is V
Larger than when R0 is applied.

Further, by connecting the resistor 10 in series, only the real part of Zc increases, so that the impedance of the variable capacitance element 6 seen through the resistor 10 moves from Zc to Zd. That is, the resistor 10 acts to increase the absolute value of the reflection coefficient of Zc when VR0 is applied and to reduce the absolute value of the reflection coefficient of Zc when VR1 and VR2 are applied. The resistor 10 is selected to have a small loss variation and a loss of about several Ω depending on the applied voltage VR of the microwave phase shifter.

By selecting such a resistor 10, the absolute value of the reflection coefficient of the variable capacitance element 6 seen through the inductive element 9, the transmission line 12 and the resistor 10 becomes substantially constant.
Therefore, similarly to the first and second embodiments, it is possible to obtain a microwave phase shifter having a characteristic that the loss is substantially constant with respect to the applied voltage VR and only the phase changes.

By connecting the resistor 10, VR
Although the change in the imaginary part of Zc becomes slightly smaller and the phase change becomes smaller, there is no practical problem by selecting the variable capacitance element 6 in which the junction capacitance Cj greatly changes with respect to the applied voltage VR.

As described above, the series circuit of the resistor 10, the transmission line 12, and the inductive element 9 is connected between the coupling terminal 4 and the variable capacitance element 6 of the 90 ° hybrid 1 and between the passing terminal 5 and the variable capacitance element 6, respectively. By doing so, it is possible to obtain a microwave phase shifter with a small loss variation with respect to the applied voltage VR.

With this structure, it is not necessary to short-circuit one end of the resistor 10, and by using the microwave integrated circuit technology, the realization is easier than in the first and second embodiments.

Fourth Embodiment FIG. 9 shows the structure of a microwave phase shifter according to a fourth embodiment, wherein 1 to 8 are the same as those in FIG.
0 is the same as the description of FIG. 1, 11 is the description of FIG. 5, and 12 is the same as the description of FIG. 7.

The basic structure is the same as that of the third embodiment except that the capacitive element 11 is used instead of the inductive element 9 shown in the third embodiment. The third embodiment can be applied to the case where the impedance of the variable capacitance element 6 is capacitive, whereas the present invention is applicable to the case where it is inductive.

FIG. 10 shows the impedance Za of the variable capacitance element 6 shown in FIG. 9, the impedance Zb of the variable capacitance element 6 seen through the capacitive element 11, and the variable capacitance seen through the capacitive element 11 and the transmission line 12. Impedance Zc of element 6
3 is an example in which the locus of the impedance Zd of the variable capacitance element 6 seen through the capacitive element 9, the transmission line 12 and the resistor 10 is represented on a Smith chart. Here, as in the first to third embodiments, the angular frequency ω is kept constant and the applied voltage VR is changed from VR1 to VR2.

The capacitive element 11 is for converting the impedance Za of the variable capacitive element 6 on the real axis of the Smith chart as shown in the second embodiment, and is seen through the capacitive element 11. The impedance of the variable capacitance element 6 moves from Za to Zb. Further, as shown in the third embodiment, the impedance of the variable capacitance element 6 is changed from Zc to Zd by interposing the transmission line 12 and the resistor 10.
Move to.

Since the transmission line 12 and the resistor 10 have the same functions as those shown in the third embodiment, the variable voltage seen through the capacitive element 11, the transmission line 12 and the resistor 10 with respect to the applied voltage VR. The absolute value of the reflection coefficient of the capacitive element 6 is almost constant.

Therefore, when the impedance of the variable capacitance element 6 is inductive, the coupling terminal 4 of the 90 ° hybrid 1 is used.
Between the variable capacitance element 6 and the passing terminal 5 and the variable capacitance element 6
A resistor 10, a transmission line 12 and a capacitive element 11 are respectively provided between them.
By connecting a series circuit of and, it is possible to obtain a microwave phase shifter with a small loss variation with respect to the applied voltage VR.

Even with this structure, it is not necessary to short-circuit one end of the resistor 10, and it is easy to realize by using the microwave integrated circuit technology.

The first to fourth embodiments described above
Then, we described a microwave phase shifter that achieves the desired phase characteristics with a small loss variation due to the applied voltage VR. Generally, in an antenna such as an active phased array antenna, which is configured by arranging a large number of modules, a temperature distribution is generated in each module, so that the absolute phase of each module also varies. Therefore, a function of compensating for the absolute phase is required.

A microwave phase shifter capable of compensating for variations in absolute phase without impairing the functions shown in Embodiments 1 to 4 will be described below.

Fifth Embodiment FIG. 11 shows the structure of the microwave phase shifter of the fifth embodiment, in which 13 is an open tip stub, 1 to 8 are the same as those in FIG. 13 of the conventional description, 9 and 10 are the same as those in FIG. 1, and 12 is the same as those in FIG. 7.

The 90 ° hybrid 1 of the third embodiment is provided with the open stubs 13 at the input terminal 2 and the isolation terminal 3, respectively. This open tip stub 1
3 has a function of delaying the absolute phase, and the longer the length, the larger the phase delay.

Usually, the provision of the open-end stub 13 deteriorates the return loss of the microwave phase shifter. However, by providing the open-end stubs 13 on the input terminal 2 and the isolation terminal 3 of the 90 ° hybrid 1 having a phase difference of 90 ° as in the present invention, the return loss is deteriorated by the two open-end stubs 13. It is offset, and the return loss deterioration can be prevented.

By providing the tip open stub 13, the loss variation and the phase characteristic due to the applied voltage VR shown in the third embodiment are not given, and therefore the tip is provided to the input terminal 2 and the isolation terminal 3 respectively as shown in this figure. By providing the open stub 13 and setting the length to a desired value, only the absolute phase between the input terminal 2 and the isolation terminal 3 can be set.

FIGS. 12 (a) and 12 (b) show examples of loss and phase characteristics with respect to the applied voltage VR of the microwave phase shifter of the present invention. The solid line shows the case without the open tip stub 13 and the dotted line shows the case. In this way, by providing the open-end stub 13, only the absolute phase can be adjusted without affecting the phase and loss with respect to VR.

Thus, by applying the microwave phase shifter of the present invention to temperature compensation of the phase of the module,
It is possible to obtain a module having a small phase fluctuation with respect to temperature and a small variation in absolute phase, and to obtain a high antenna gain.

The case where the open-ended stub 13 is provided at the input terminal 2 and the isolation terminal 3 of the microwave phase shifter of the third embodiment has been described here, but the first embodiment, the second embodiment and the It may be applied to that of the fourth embodiment.

In the above example, the case where it is applied to the active phased array antenna module has been described. However, the microwave phase shifter of the first to fifth embodiments is used as a multiport amplifier or a power combining type amplifier. May be applied to the FE as the variable capacitance element 6.
You may use T.

[0070]

According to the first aspect of the invention, the impedance of the variable capacitance element can be applied in a frequency band where the impedance is capacitive, and the control voltage VR can provide characteristics that the loss variation is small and only the phase changes. By applying this to temperature compensation of the phase of the active phased array antenna module, it is possible to obtain a module whose phase fluctuation is small with respect to temperature and to realize an antenna with high gain. In addition, there is no need to perform amplitude compensation of the module in consideration of the loss variation of the microwave phase shifter, and there is an advantage that the amplitude control becomes simple.

According to the second invention, the variable capacitance element can be applied in a frequency band in which the impedance is inductive,
With the control voltage VR, it is possible to obtain the characteristic that the loss variation is small and only the phase changes, and there is an advantage that the DC blocking capacitor is unnecessary and the cost can be reduced.

According to the third invention, the variable capacitance element can be applied in a frequency band in which the impedance is capacitive,
By the control voltage VR, it is possible to obtain the characteristic that the loss variation is small and only the phase changes. In particular, there is an advantage that it is not necessary to short-circuit one end of the resistor and it can be easily realized by the microwave integrated circuit technology.

According to the fourth invention, the variable capacitance element can be applied in the frequency band in which the impedance is inductive,
With the control voltage VR, it is possible to obtain the characteristics that the loss variation is small and only the phase changes, and the DC blocking capacitor is not required. Moreover, it is not necessary to short-circuit one end of the resistor and it can be easily realized by the microwave integrated circuit technology. There are advantages.

According to the fifth aspect of the invention, the control voltage VR can provide characteristics that the loss variation is small and only the phase changes, and also has an absolute phase adjusting function, which is used for the active phased array antenna. By applying it to the temperature compensation of the phase of the module, it is possible to obtain a module having a small phase variation with respect to temperature and a small variation in absolute phase. Thereby, there is an advantage that a higher performance antenna can be realized.

[Brief description of drawings]

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

FIG. 2 is a diagram showing an impedance locus of the variable capacitance element used in the microwave phase shifter according to the first embodiment of the present invention.

FIG. 3 is a diagram showing an example of phase and loss characteristics of the microwave phase shifter of the first embodiment according to the present invention.

FIG. 4 is a diagram showing the configuration of another example of the microwave phase shifter according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of a microwave phase shifter according to a second embodiment of the present invention.

FIG. 6 is a diagram showing an impedance locus of the variable capacitance element used in the microwave phase shifter according to the second embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a microwave phase shifter according to a third embodiment of the present invention.

FIG. 8 is a diagram showing an impedance locus of the variable capacitance element used in the microwave phase shifter according to the third embodiment of the present invention.

FIG. 9 is a diagram showing a configuration of a microwave phase shifter according to a fourth embodiment of the present invention.

FIG. 10 is a diagram showing an impedance locus of the variable capacitance element used in the microwave phase shifter according to the fourth embodiment of the present invention.

FIG. 11 is a diagram showing a configuration of a microwave phase shifter according to a fifth embodiment of the present invention.

FIG. 12 is a diagram showing an example of phase and loss characteristics of the microwave phase shifter of the fifth embodiment according to the present invention.

FIG. 13 is a diagram showing a configuration of a conventional microwave phase shifter.

FIG. 14 is a diagram showing an impedance locus of a variable capacitance element used in a conventional microwave phase shifter.

FIG. 15 is a diagram showing an example of phase and loss characteristics of a conventional microwave phase shifter.

[Explanation of symbols]

1 90 ° hybrid, 2 input terminals, 3 isolation terminals, 4 coupling terminals, 5 pass terminals,
6 variable capacitance element, 7 choke circuit, 8 DC power supply 9 inductive element, 10 resistance, 11 capacitive element,
12 transmission lines, 13 open-end stubs

Claims (5)

[Claims] 1. A variable capacitance element such as a varactor diode or a FET is connected between a coupling terminal of a 90 ° hybrid having an input terminal, a coupling terminal, a passage terminal and an isolation terminal and the ground, and between a passage terminal and the ground, respectively. In the microwave phase shifter configured as described above, an inductive element is connected in series to each of the variable capacitance elements, and resistors are respectively connected between the coupling terminal and the ground and between the passing terminal and the ground. Phase shifter. 2. A variable capacitance element such as a varactor diode or a FET is connected between a 90 ° hybrid coupling terminal having an input terminal, a coupling terminal, a passage terminal and an isolation terminal and the ground, and between a passage terminal and the ground, respectively. In the microwave phase shifter, the microwave is characterized in that a capacitive element is connected in series to each of the variable capacitance elements, and resistors are respectively connected between the coupling terminal and the ground and between the passing terminal and the ground. Phase shifter. 3. A variable capacitance element such as a varactor diode or a FET is connected between a 90 ° hybrid coupling terminal having an input terminal, a coupling terminal, a passage terminal and an isolation terminal and the ground, and between the passage terminal and the ground, respectively. In the microwave phase shifter configured as described above, a series circuit including a resistance and a transmission line having a quarter wavelength at a desired frequency and an inductive element is provided between the coupling terminal and the variable capacitance element and between the pass terminal and the variable capacitance element, respectively. A microwave phase shifter characterized by being connected. 4. A variable capacitance element such as a varactor diode or a FET is connected between a coupling terminal of a 90 ° hybrid having an input terminal, a coupling terminal, a passage terminal and an isolation terminal and the ground, and between a passage terminal and the ground, respectively. In the microwave phase shifter configured as described above, a series circuit including a resistance and a transmission line having a quarter wavelength at a desired frequency and a capacitive element is provided between the coupling terminal and the variable capacitance element and between the pass terminal and the variable capacitance element, respectively. A microwave phase shifter characterized by being connected. 5. The microwave phase shifter according to claim 1, wherein open-ended stubs are respectively connected to the input terminal and the isolation terminal of the 90 ° hybrid.