JPH01218108A - High frequency oscillator - Google Patents

Abstract

PURPOSE:To switch an output of an SAW oscillator and a magnetostatic wave oscillator with simple constitution by allowing the SAW oscillator and the magnetostatic wave oscillator to use a transducer and an amplifier in common. CONSTITUTION:A switch 6 selects a bias input Ea and a switch 8 is turned on, then the gain of the amplifier 4 is Ga, a current flows to coils 31, 32 to generate a magnetostatic wave field BO shown in the arrow 13, an MSW delay element 2 applies MSW oscillation but an SAW delay element 12 does not make SAW oscillation. The switch 6 selects a bias input Eb and the switch 8 is turned off, then the gain of the amplifier 4 is Gb, no current flows to the coils 31, 32 and a magnetostatic wave field BO is zero, then no MSW is propagated and no MSW oscillation is caused in the MSW delay element 2, but the SAW delay element 12 makes SAW oscillation. Thus, the transducers 22, 23 and the amplifier 4 are used in common. Then the switching of MSW and SAW is executed simply by the change in the gain of amplifier 4 and the intensity of magnetostatic field.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a high frequency oscillation circuit that can switch between wideband output and highly stable output.

(Prior Art) Surface acoustic waves (Surface Acoustic Waves) have conventionally been used as highly stable fixed frequency microwave signal sources.
There is one using a device (hereinafter referred to as SAW).

On the other hand, as a variable frequency microwave signal source, a magnetostatic wave (magnetic wave: Magnet) propagating in a YIG thin film is used.

There is one using a 5tatic wave (MSW) element.

FIG. 2 shows a diagram of the principle of magnetostatic wave propagation. When a DC magnetic field HO is applied to a YIG (yttrium-iron-garnet) single crystal 41 in the direction of an arrow 42, the magnetic moment of this YIG single crystal 41 changes from the DC magnetic field. Line up in a 14° direction. This Y
Microwaves are supplied to the IG single crystal 41 from a transducer 43. As a result, the magnetic moment begins to precess as shown at 45. The rotational frequency of this precession is called the magnetic resonance frequency. When the microwave frequency approaches this magnetic resonance frequency, the microwave is pulled into precession and its speed suddenly drops. Such microwaves are particularly called magnetostatic waves, and their resonance frequency is proportional to the DC magnetic field H. By further providing a transducer similar to 43 at the destination of the magnetostatic wave 44, the magnetostatic wave can be converted into an electric signal again, thus forming a magnetostatic wave delay element.

(Problem to be solved by the invention) For example, when wideband sweeping is performed with a magnetostatic wave oscillator using an inexpensive signal source, and frequency calibration is performed using the fundamental wave and harmonics of the SAW oscillator. In addition, if it is desired to switch between two types of microwave signals, it is possible to separately provide both venders and switch between them using a high frequency switch, but since there are many common parts, this is wasteful in terms of construction.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to realize a high-frequency oscillator with a simple configuration that can switch the output of a SAW oscillator and a magnetostatic wave oscillator.

(Means for Solving the Problems) A high frequency order oscillator according to the present invention includes a magnetostatic wave delay element, a surface acoustic wave delay element that shares the input transducer and output transducer of the magnetostatic wave delay element, and the output transducer. A variable gain amplifier that amplifies an output signal and outputs it to the input transducer, a static magnetic field applying means that applies a static magnetic field to the magnetostatic wave delay element, and a gain control means that controls the gain of the variable gain amplifier, The present invention is characterized in that it is configured to switch between a magnetostatic wave delay element and a surface acoustic wave delay element.

(Function) The configuration can be simplified because the SAW oscillator and the magnetostatic wave oscillator share a transducer and an amplifier.

(Example) The present invention will be explained in detail below using the drawings. FIG. 1 is a configuration explanatory diagram showing one embodiment of a high frequency oscillator according to the present invention. In the SAW element 1, 11 is a conductive substrate for grounding, and 12 is a SAW propagation path made of LiNbO formed on this substrate ll (in the figure, on the lower surface of the substrate 11). In the magnetostatic wave delay line 2, 21 is the propagation path (m) of the magnetostatic wave made of YIG (yttrium-Chichi-Carnet)
(hereinafter referred to as Nl5W propagation path), 22 is MSW propagation path 21
a transducer for microwave input provided on the
Similarly, 23 is an output transducer. In the figure, the MSW propagation path 21 and the SAW propagation path 12 are shown to be spaced apart, but in reality, they are integrated with transducers 22 and 23 sandwiched between them, as indicated by the broken line arrows. 4
5 is a variable gain type amplifier for inputting the microwave output of the output transducer 23 to form an MSW oscillation loop; 5 inputs the output of the amplifier 4 through its first port, and inputs it through the second port. A directional coupler outputs the microwave to the transducer 22 and also outputs the microwave to the outside via a third port. 6 is a changeover switch that selects and applies bias manual power Ea or Eb to the gain control terminal of the amplifier 4. It is. 31 and 32 are coils forming a static magnetic field applying means for applying a static magnetic field BO to the MSW propagation path 21, 7 is a coil drive circuit for driving the coils 31 and 32, and 8 is a coil for driving the drive circuit 7 and the coils 31 and 32. This is a switch that is connected between the two to turn it on and off.

The operation of the high frequency oscillator having the above configuration will be explained next. In the above device, the loss S of the SAW delay line 1 is M S W
It is designed to be larger than the loss LM of delay line 2. That is, LM < Ls (1) Also, output transducer 23 - amplifier 4 → input transducer 22
Let L be the sum of losses between.

Also, amplifier 4 when bias human power Ea and Eb are connected
When the gains of are Ga and Gb, respectively, Ga < Gb
...There is the relationship (2).

Next, each operation mode will be explained.

B. When the bias input Ea is selected with the MSW oscillation mode switch 6 and the switch 8 is turned on, the gain of the amplifier 4 becomes Ga, current flows through the coils 31 and 32, and the static magnetic field B shown by the arrow 13
0, and Li+L=Ga...(3), so M S
W delay element 2 performs M SW oscillation, but L s + L
> Ga ・= < 4), so SAW
The delay element 12 does not perform SAW oscillation. 10 is an arrow indicating the state of propagation of MSW during MSW oscillation.

When the bias manual Eb is selected with the SAW oscillation mode switch 6 and the switch 8 is turned off, the gain of the amplifier 4 becomes Gb, and since no current flows through the coils 31 and 32 and the static magnetic field B0 becomes 0, M
Although the SW does not propagate and MSW oscillation does not occur in the MSW delay element 2, the SAW delay element 12 performs SAW oscillation because Ls + L = Gb - (5). 9
is the state of SAW propagation during SAW oscillation (more precisely, SAW
This is an arrow indicating the propagation (propagation on the surface of the propagation path 12).

The microwave outputs in each of the above modes are taken out to the outside via the directional coupler 5.

According to the high frequency oscillator having such a structure, the transducer and the amplifier can be used in common, so the structure is simple.

Furthermore, switching between MSW and SAW can be easily performed by changing the amplifier gain and static magnetic field strength.

In the above embodiment, in order to prevent MSW from occurring during SAW oscillation, the static magnetic field BO does not necessarily have to be set to O, and the MSW oscillation when changing the oscillation frequency of MSW by changing the magnetic field B0 Set the loop gain of the loop to 1
An amplifier with frequency characteristics such as a groove at the end may be used.

Furthermore, if the frequency characteristics of the amplifier gain are configured to be switchable between the MSW mode and the SAW mode, both modes can be switched simply by switching the amplifier gain, and the on/off switch 8 for the coil 31 can be made unnecessary. In this case, it is not necessary that the losses of both delay elements satisfy Lr1<Ls.

In addition, the SAW propagation path 12 is not limited to LtNbOi.
Crystal, LiTaO3, etc. can also be used.

In addition, in the above embodiment, the direction of application of the static magnetic field is perpendicular to the YIG plane to excite the magnetostatic forward #product wave, but this is not limitative. Volume waves may also be excited.

It is also possible to generate high frequency oscillations other than microwaves.

(Effects of the Invention) As described above, according to the present invention, a high frequency wave oscillator capable of switching the output of a highly stable SAW oscillator and a broadband magnetostatic wave oscillator can be realized with a simple configuration.

[Brief explanation of the drawing]

Fig. 1 is a structural perspective view showing one embodiment of a high frequency oscillator according to the present invention, and Fig. 2 is an explanatory diagram showing the principle of a magnetostatic wave element. Magnetic wave delay element, 4... Variable gain amplifier, 6... Gain control means, 22... Input transducer, 23... Output transducer, 31.32... Static magnetic field application means. Figure 2 42 4S

Claims (1)

[Claims] A magnetostatic wave delay element, a surface acoustic wave delay element that shares an input transducer and an output transducer of the magnetostatic wave delay element, and a variable gain amplifier that amplifies an output signal from the output transducer and outputs it to the input transducer. , comprising a static magnetic field applying means for applying a static magnetic field to the magnetostatic wave delay element, and a gain control means for controlling the gain of the variable gain amplifier, and configured to switch between the magnetostatic wave delay element and the surface acoustic wave delay element. A high frequency oscillator characterized in that it is configured as follows.