JPS639302A - Phase shifter - Google Patents

Abstract

PURPOSE:To form an inexpensive phase shifter suitable for a microwave integrated circuit by coupling a strip line resonator mounted with a varactor diode on the rear side to a coupling terminal of a strip line directional coupler and extracting an output from an isolator port of the strip line directional coupler. CONSTITUTION:A signal inputted from an input terminal 11 passes through a directional coupler 15, a part appears at a coupling port 20, is reflected totally at an open end 23 via a phase shifter 21 and a line 22, appears at the coupling port 20 again via the line 22 and the phase shifter 21 as a reflected wave and appears at an output terminal 13 of the phase shifter 21 as an output through a coupling port 15. The phase of an output wave at the output terminal 13 is controlled by varying the phase of the phase shifter 21. The phase shifter 21 consists of a resonator 16 being a strip line, a coupling line 18, a varactor diode 17, a low pass filter 19, and a control terminal 14.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a microwave band phase shifter used in various measuring instruments or phase detectors.

2. Description of the Related Art Microwave band phase shifters are essential circuits used in phase compensation circuits, phase detection circuits, and the like. Usually a multi-stage LC using variable capacitance diodes (varactor diodes)
circuit or distributed constant L PF circuit is used,
When constructed with one varactor diode, a circuit as shown in FIG. 3 which combines a circulator and a resonant circuit is known.

In Figure 3, 11 is an input terminal, 13 is an output terminal, 1
4 is a phase shifter control terminal, 16 is a resonator, 17 is a resonator 16
Varactor diodes, one part of the LC
25 is a circulator.

If we keep the voltage applied to the control terminal 14 constant,
The resonator 16 resonates at a certain frequency far, and its admittance changes significantly near this frequency. In this state, fO near the frequency fa applied from the input terminal 11
A signal with a frequency of . By the way, when the voltage applied to the control terminal 14 is changed, the resonator 16
Since the resonant frequency of also changes, as a result, the frequency fo
The admittance at will also change. Therefore, since the reflected phase at the terminal 26 also changes, the phase of the wave reflected at the output terminal 13 also changes. That is, it becomes possible to change the output phase by controlling the control voltage.

Problems to be Solved by the Invention However, although the circuit shown in FIG. 3 is stable in operation and can control a phase amount of up to 180° with one varactor diode 17, it is expensive due to the use of the circulator 25. Because it is difficult to manufacture on a single dielectric substrate,
In view of the above drawbacks of the prior art, the present invention aims to realize a phase shifter that is inexpensive and suitable for microwave integrated circuits.

Means for Solving the Problems The present invention provides a coupling terminal of a strip line directional coupler,
A stripline resonator equipped with a variable capacitance diode is coupled to the stripline directional coupler, and the output is taken out from an isolated port of the stripline directional coupler.

Operation The present invention achieves the above object by utilizing the directionality of the strip line directional coupler with the above configuration.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view of a phase shifter in an embodiment of the present invention, and FIG. 2 is a conceptual circuit diagram for explaining the operation of FIG. 1. First, the basic operation of phase change will be explained using FIG.

In Figure 2, 11 and 12 are input and output terminals, respectively.
3 is one terminal of the directional coupler, which serves as an output as a phase shifter. 15 is a directional coupler, 20 is a coupling port of the directional coupler 15, 21 is a phase shifter, 22 is a line, and 23 is a terminal, which is an open end here.

The signal now input from the input terminal 11 is sent to the directional coupler 15
A part of the wave is reflected at the coupling port 20, passes through the phase shifter 21 and line 22, is totally reflected at the open end 23, and returns to the coupling port 20 as a reflected wave via the line 22 and phase shifter 21. The signal passes through the coupling port 15 as it is and is generated at the output end 13 of the phase shifter 21 as an output.

The phase of the output wave at the output end 13 can be controlled by changing the phase of the phase shifter 21. Note that the line 22 is not an essential component, and the same effect will occur even if the phase shifter 21 is terminated in an open or short circuit.

FIG. 1 shows the phase shifter 21 in FIG.
7, the reduced pass filter 19, and the control terminal 14 are used instead.

The resonator 16 is coupled to the coupling port of the directional coupler 15, and is also coupled to the varactor diode 17, so that the reflection phase shifter can be changed by changing the resonance frequency using the control voltage vt.

By adopting such a circuit configuration, all the circuits can be integrated on a single dielectric substrate as shown in Figure 1.
Moreover, a circulator is not required, and an inexpensive and highly reliable phase shifter can be realized.

Moreover, the amount of phase change can be 180° with one varactor diode 17, similar to the conventional one shown in FIG.

Effects of the Invention As described above, the present invention provides an inexpensive and highly reliable microwave band phase shifter, which includes a phase compensation circuit,
It can be applied to detection circuits, and its industrial value is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a plane circuit diagram of a phase shifter according to an embodiment of the present invention, FIG. 2 is a conceptual plane circuit diagram of FIG. 1, and FIG. 3 is a plane circuit diagram of a conventional phase shifter. 11...Input terminal, 13...Output terminal, 14...
Control terminal, 15... Directional coupler, 16... Resonator, 17... Varactor diode. Name of agent: Patent attorney Satoshi Nakao and 1 other person No. 1
rXJ Figure 3

Claims (1)

[Claims] A stripline resonator equipped with a variable capacitance diode is coupled to the coupling terminal of the stripline directional coupler,
A phase shifter configured to take out an output from an isolated port of the stripline directional coupler.