JPH01109904A - Magnetostatic wave oscillation circuit - Google Patents

Abstract

PURPOSE:To obtain a microwave band oscillation circuit with simple constitution and less fluctuation in the output frequency by combining a resonance circuit comprising only a magnetostatic wave delay line and a negative resistance circuit so as to constitute an oscillation circuit. CONSTITUTION:A microwave generated from a negative resistance circuit 20 is led to a YIG thin film 11 by a transducer 13. Since a DC magnetic field is fed to the thin film 11 by a magnetic field generator 23, a magnetostatic wave 4 is generated. The magnetostatic wave 4 is received by a transducer 17 and restored to the circuit 20, power is increased and returned to the transducer 13. The circuit is oscillated in a frequency equivalent to the circulated time. In order to extract the power efficiently, the output is outputted externally from the terminal 22 via a matching circuit 202 and a buffer amplifier 21. Since the oscillation frequency is decided by the intensity H0 of the impressed static magnetic field, so long as the intensity H0 is stable, the frequency is made constant.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to improvement of a microwave oscillation circuit using magnetostatic waves.

(Prior art) Figure 2 shows magnetostatic resonance (magnetic resonance: MaQnetOstat).
ic Wave: MSW). YIG(
When a DC magnetic field Ho is applied to Yttrium-Iron-Garnet I-) fil crystal 1 in the direction of arrow 2, this YIG
The magnetic moment of the single-connected product 1 is aligned in the direction of the DC magnetic field Ho. Microwaves are supplied to this YIG single crystal 1 from a transducer 3. As a result, the magnetic moment begins to precess as shown in 5. The rotational frequency of this precession is called the magnetic resonance frequency. When the frequency of the microwave approaches this magnetic resonance frequency, the microwave is drawn into precession and the speed drops suddenly. Such microwaves are particularly called magnetostatic waves, and their resonant frequency is proportional to the direct current magnetic field. By further providing a transducer similar to 3 to the traveling light of the magnetostatic wave, the magnetostatic wave can be converted into an electric signal again, and in this way, a magnetostatic wave delay line is formed.

FIG. 3 shows an example of a conventional magnetostatic wave oscillation circuit using a magnetostatic wave delay line. The magnetostatic wave delay 11N10 is mounted on a GGG (gadolinium-gallium-garnet) substrate 16 with a thickness of 20μ.
The structure is such that a YIG (yttrium-iron-garnet) film 11 of about m thickness is formed, and transducers 13 and 17 for microwave input/output are provided thereon. The output of the magnetostatic delay line 10 is connected to a microwave amplifier 18, and the output of the microwave amplifier 18 is connected to a directional coupler 19.
The output of the directional coupler is connected to the input of the magnetostatic delay line 10 to form an oscillation loop.

The oscillation frequency of such an oscillator circuit is determined by the loop-period time and the wavelength selectivity of transducers 13 and 17.

(Problem to be solved by the invention) However, since amplifiers generally generate noise,
The above configuration causes phase fluctuations that change rapidly within 1 second, that is, fluctuations in the delay characteristics, and the oscillation frequency is greatly affected. Another problem is that it is difficult to make a compact and broadband directional coupler.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to realize a microwave band oscillation circuit using static magnetic waves with less fluctuation in output frequency.

(Means for Solving the Problems) The present invention relates to a magnetostatic wave oscillation circuit using a magnetostatic wave delay line whose propagation time changes depending on the strength of an applied DC magnetic field. The input terminal and the output terminal of the resonant element are connected to form a resonant element, and both terminals are connected to a negative resistance section.

(Function) Since the oscillation circuit is configured by a combination of a resonant circuit consisting of only a magnetostatic wave delay line and a negative resistance circuit, output frequency fluctuation can be reduced.

(Example) The present invention will be explained in detail below using the drawings.

FIG. 1 is a block diagram showing an embodiment of a magnetostatic wave oscillation circuit according to the present invention. The same parts as in FIG. 3 are given the same symbols and the explanation is omitted. In the magnetostatic wave oscillation circuit 10a, 18 and 19 are known means for preventing the magnetostatic wave 4 from being reflected at the end face and have an adverse effect, P is a point where the transducers 13 and 17 are connected, and 20 is a point at which this point P is connected. Negative resistance circuit to be connected, 201 is a transistor whose emitter terminal is connected to the point P, L is this transistor 2
202 is a matching circuit whose one end is connected to the collector terminal of the transistor 201; 21 is an inductance whose input terminal is connected to the other end of the matching circuit 202; The connected buffer amplifier 22 is an output terminal to which the output of this buffer amplifier 21 is connected.

The operation of the device having one configuration as described above will be explained next.

Microwaves generated by the negative resistance circuit 20 are introduced into the Y I G and thin film 11 by the transducer 13 . Y
Since a DC magnetic field is applied to the IG film 11 by the magnetic field generator 23, the magnetostatic wave 4 in the surface magnetostatic wave mode is generated according to the principle explained in FIG. The propagation direction of the static magnetic wave 4 is determined by the direction of the DC magnetic field 2. This static magnetic wave is received by the transducer 17, returned to the negative resistance circuit 20, has its power increased, and is introduced into the transducer 13 again. As a result, it oscillates at a frequency determined by the time it takes to go around the loop. The oscillation output is generated by a matching circuit 202 and a buffer amplifier 2 in order to extract power efficiently.
1 to the outside from the output terminal 22. The output frequency is determined by the strength H0 of the DC magnetic field 2 by the magnetic field generator V123.
can be changed by changing the propagation time of the magnetostatic wave.

According to the magnetostatic wave oscillation circuit having such a configuration, the oscillation frequency is determined from the transducer 13 to the transducer 17.
→Point P→Since the loop of the transducer 13 does not include an amplifier or a directional coupler, there are no strange S elements such as noise.

Therefore, since the oscillation frequency is determined by the strength Ho of the applied static magnetic field and the wavelength selectivity of the transducer, the oscillation frequency can be kept constant as long as Ho is stable. Phase fluctuations caused by the amplifier 21 and the like only appear in the output as they are, and do not affect the oscillation frequency at all.

Furthermore, since the configuration does not include a directional coupler, it is easy to downsize.

In the above embodiment, an FET may be used in place of the transistor 201 in the negative resistance section 20, and its base (or gate) electrode may be grounded via the inductance L. Various other known circuits can be used as the negative resistance section 20.

Further, in the above embodiment, magnetostatic surface waves are generated in accordance with the direction of application of the DC magnetic field, but magnetostatic waves 81 may be generated by applying the DC magnetic field in other directions.

(Effects of the Invention) As described above, according to the present invention, an oscillation circuit for a microwave band using static magnetic waves with little output frequency fluctuation can be produced.
This can be realized with a tIt1i configuration.

[Brief explanation of the drawing]

Fig. 1 is a configuration block diagram showing an embodiment of the magnetostatic wave oscillation circuit according to the present invention, Fig. 2 is an explanatory diagram showing the principle of a magnetostatic wave delay line, and Fig. 3 is a diagram of a conventional magnetostatic wave optical one-line circuit. FIG. 2 is a configuration block diagram showing an example. 2... DC magnetic field, 10a... Magnetostatic wave delay line, 20.
...Negative resistance section. Figure 3

Claims (1)

[Claims] In a magnetostatic wave oscillation circuit using a magnetostatic wave delay line whose propagation time changes depending on the strength of the applied DC magnetic field, a resonant element is constructed by connecting the input terminal and output terminal of the magnetostatic wave delay line, and both terminals are connected to a negative polarity. A magnetostatic wave oscillation circuit characterized by being connected to a resistive part.