JPH05259737A - Dielectric oscillator - Google Patents

Abstract

PURPOSE:To obtain an optional frequency by forming a resonator with plural dielectric resonators each having a different resonance frequency, one active element, and a variable reactance element and optimizing the electric length of each resonator and the active element on a microstrip line so as to vary the reactance of the reactance element. CONSTITUTION:A FET 11 as an active element, a varactor 12 being a varactor diode, and two dielectric resonators 13, 14 having different frequencies f1, f2 are employed and one of the two frequencies is selected. Microstrip lines 15, 16 whose impedance is 50ohms are used for transmission lines, one end of the line 15 is connected to a gate terminal of the FET 11 and the other end is connected respectively to a 50ohm termination resistor 17, the resonators 13, 14 are provided to the line 15 and they are coupled magnetically. Then, a feedback circuit is formed by the resonators 13, 14 connecting to a gate terminal of the FET and the varactor 12 connecting to the source, electric lengths theta1, theta2 from the gate terminal of the FET 11 is optimized to change the feedback static capacitance of the varactor 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric oscillator, and more particularly to a dielectric oscillator using a variable reactance element, which is used in radars, satellite broadcasting receivers, etc. in addition to measuring instruments.

[0002]

2. Description of the Related Art Conventionally, as a dielectric oscillator of this type,
For example, there is one shown in the configuration diagram of FIG. That is, this dielectric oscillator G has n dielectric oscillators 1, 2, 3 ... N each having a different oscillation frequency and one of the n oscillators 1, 2, 3 ... N. Single-pole multi-throw switch S for selecting and outputting from the output end
It is composed of W and.

[0003]

However, such a conventional dielectric oscillator requires as many oscillators as the number of different oscillation frequencies to be selected, and as the number increases, single-pole / multi-throw. There is a problem that the shape switch SW becomes complicated, the whole circuit becomes complicated, and power consumption becomes large.

On the other hand, the degree of suppression of the output of the oscillator of the non-selected frequency is determined by the insulating characteristic of the switch SW particularly in high frequency, and it is difficult to completely suppress the output of the oscillator other than the selected frequency. There were also problems.

The present invention has been made in view of the above points,
It is an object of the present invention to solve the above problems and provide a dielectric oscillator in which one oscillator can arbitrarily select one of a plurality of different oscillation frequencies.

[0006]

The structure of the present invention for achieving the above-mentioned object is a dielectric comprising a plurality of dielectric resonators each having a different resonance frequency, one active element, and a variable reactance element. It is an oscillator, and its detailed configuration is as follows.

(1) The active element is a field effect transistor (hereinafter, simply referred to as FET), the gate terminal of the FET is connected to a microstrip line whose one end is connected to the microstrip line. Each of the dielectric resonators is magnetically coupled to each other at positions separated by an electrical length suitable for the resonance frequency, and the FET is also provided.
The variable reactance element is connected to the source terminal of the FET, the reactance value of the variable reactance element is changed, and the resonance frequency of any one of the dielectric resonators is changed from the drain terminal of the FET. It is characterized by outputting.

(2) The active element is a FET, and a microstrip line having one end connected to the gate terminal of the FET has an electrical length suitable for the resonance frequency from the connection end with the FET. The dielectric resonators are magnetically coupled to each other at separate positions, and
To the source terminal of the FET, the variable reactance element whose reactance value changes according to the change of the applied voltage is connected, while from the drain terminal side of the FET,
A divider for dividing the output frequency, a reference frequency oscillator,
Phase lock circuit comprising a phase detector for detecting the phase between the frequency division frequency of the frequency divider and the reference frequency of the reference frequency oscillator, and a low-pass filter for passing the detection voltage of the phase detector. Connected to the variable reactance element, changing the division ratio of the divider,
The resonance frequency of any one of the dielectric resonators is output from the drain terminal of the FET.

[0009]

Since the present invention is configured as described above, even if the number of different oscillation frequencies to be selected increases, each dielectric resonator arranged on the microstrip line and the FET of the active element are The electric length of the variable reactance element is changed and the reactance value of the variable reactance element is changed.
By changing the frequency division ratio of the frequency divider in the phase lock circuit connected from ET to the variable reactance element,
The resonance frequency of any one of the resonators is selected, and the F
It can be output from ET. Moreover, since the other oscillation frequencies not selected are not oscillated, they do not appear at all in the output of the FET.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be illustratively described in detail below with reference to the drawings.

(First Embodiment) FIG. 1 is a structural circuit diagram showing a first embodiment of a dielectric oscillator according to the present invention.
ET11, a varactor (so-called variable capacitance diode) 12 as a variable reactance element, and two dielectric resonators 13 and ₁ having respectively different resonance frequencies f ₁ and f _2.
This is an example in which one of the two frequencies using 4 is selected and switched.

In the figure, 50Ω microstrip lines 15 and 16 are used as transmission lines, and one end of the line 15 is F
ET11 gate terminal, the other end is a 50Ω termination resistor 17
And the dielectric resonators 13 and 14 are disposed on the microstrip line 15 and are magnetically coupled.

The varactor 12 is connected to the source terminal of the FET 11, and a control voltage for making its capacitance variable is applied from the reverse application voltage input terminal 17. Reference numerals 18 and 19 are DC blocking capacitors, 20 and 21 are bias coils for the FET 11, 22 is an open stub for matching, and 23 is a load resistor of 50Ω.

The dielectric oscillator of the present embodiment is based on the principle of a negative resistance oscillator, and by utilizing the fact that the output impedance of the FET 11 exhibits a negative resistance by adding a feedback circuit to the FET 11. ..

In FIG. 1, the dielectric resonators 13 and 14 connected to the gate terminal of the FET 11 and the varactor 12 connected to the source terminal form a feedback circuit.

By optimizing the values of the electrical lengths θ ₁ and θ ₂ from the gate terminal of the FET 11 on the microstrip 15, when the feedback capacitances of the varactor 12 are c ₁ , respectively. Frequency f
_{When 1} and c _2, the frequency is f ₂ and a negative resistance is obtained.

(Second Embodiment) FIG. 2 is a constitutional circuit diagram showing a second embodiment of the present invention. The same members as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. In FIG. 2, reference numeral 31 is a coupler for extracting a part of the oscillation output, and the extracted output frequency f ₀ is frequency-divided by a frequency divider 32 to 1 / N (where N is a frequency division ratio) and f _0. The frequency of / N is input to one input terminal of the phase detector 33.

At the other input end of the phase detector 33,
The reference frequency f _s from the reference frequency oscillator 34 is input, where the frequency of f ₀ / N is the reference frequency f s.
It is compared in phase with _s . When there is a phase difference between the f ₀ / N frequency and the reference frequency f _s , a DC voltage corresponding to the phase difference is output from the phase detector 33.

The DC voltage output from the phase detector 33 passes through the loop filter (low pass filter) 35 and is input to the reverse applied voltage input terminal 17. This voltage changes the capacitance of the varactor 12 and finally locks the oscillation output frequency of the entire oscillator at f ₀ .

By a circuit from the coupler 31 to the reverse applied voltage input terminal 17, a so-called phase lock (pha) is provided.
(se lock) circuit 36, and by changing the frequency division ratio N of the frequency divider 32 in the circuit 36, the frequencies f ₁ and f _{2 of the} dielectric resonators 13 and 14 respectively.
It is possible to obtain a phase-locked output of the oscillation frequency f ₁ or f ₂ by selecting any of the above frequencies.

Note that the technique of the present invention is not limited to the technique in the above-described embodiment, and may be implemented by means of another aspect having a similar function, and the technique of the present invention can be variously modified within the scope of the above configuration. Can be changed or added.

[0022]

As is apparent from the above description, according to the dielectric oscillator of the present invention, an oscillator including a plurality of dielectric resonators each having a different resonance frequency, one active element, and a variable reactance element. In addition, while optimizing the electrical lengths of the respective resonators arranged on the microstrip line and the FET as an active element, the reactance value of the variable reactance element is changed to select one of the resonators. The resonance frequency can be selected and output from the FET.

Further, by changing the frequency division ratio of the frequency divider in the phase-locked circuit which feeds back from the output side of the FET to the variable reactance element, similarly, any one resonance frequency of the resonator is selected. However, it can be output from the FET.

Therefore, one dielectric oscillator can arbitrarily select one of a plurality of different oscillation frequencies. At the same time, the oscillation frequency that is not selected is not oscillated, so that it is completely suppressed and has no influence on others.

[Brief description of drawings]

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

FIG. 2 is a configuration circuit diagram showing a second embodiment of the present invention.

FIG. 3 is a configuration diagram showing a conventional dielectric oscillator.

[Explanation of symbols]

 11 FET (Field Effect Transistor) 12 Varactor (Variable Capacitance Diode) 13, 14 Dielectric Resonator 15, 16 Microstrip Line 17 Reverse Applied Voltage Input Terminal 31 Coupler 32 Frequency Divider 33 Phase Detector 34 Reference Frequency Oscillator 35 Low Band filter 36 Phase lock circuit N division ratio

Claims (2)

[Claims] 1. A dielectric oscillator comprising a plurality of dielectric resonators each having a different resonance frequency, one active element, and a variable reactance element, wherein the active element is a field effect transistor (hereinafter simply referred to as FE).
T), the dielectric strip is provided at a position separated by an electrical length suitable for the resonance frequency from a connection end with the microstrip line, one end of which is connected to the gate terminal of the FET. A resonator is magnetically coupled, the variable reactance element is connected to the source terminal of the FET, and the reactance value of the variable reactance element is changed to change the dielectric value of any one of the dielectric resonators. A dielectric oscillator, wherein a resonance frequency of a body resonator is output from a drain terminal of the FET. 2. A dielectric oscillator comprising a plurality of dielectric resonators each having a different resonance frequency, one active element, and a variable reactance element, wherein the active element is a FET, and a gate of the FET. To the microstrip line whose one end is connected to the terminal,
The dielectric resonators are magnetically coupled to each other at a position separated from the connection end with the FET by an electrical length suitable for the resonance frequency, and the voltage applied to the source terminal of the FET is changed. The variable reactance element whose reactance value changes is connected, and on the other hand, from the drain terminal side of the FET, a divider for dividing the output frequency, a reference frequency oscillator, a dividing frequency of the divider, and the Phase lock composed of a phase detector that detects the phase of the reference frequency of the reference frequency oscillator and a low-pass filter that passes the detection voltage of the phase detector.
lock) circuit is connected to the variable reactance element, the frequency division ratio of the frequency divider is changed, and the resonance frequency of any one of the dielectric resonators is changed to the FE
A dielectric oscillator characterized in that the output is made from the drain terminal of T.