JPH06177643A - Magnetostatic wave oscillation circuit - Google Patents

Abstract

PURPOSE:To prevent oscillation characteristic from being deteriorated by increasing an interval of discontinuous points of an oscillated frequency to sweep the oscillating frequency continuously over a broad band. CONSTITUTION:An epoxy resin group adhesives is applied to other major side opposite to one major side of a GGG single crystal substrate on which a YIG film of a magnetostatic wave resonator 1 is formed, the resonator is fixed to a gap, a pad electrode and a conductor plate are connected by a copper-made connecting plate and the pad electrode and a stub are connected by a copper- made connecting plate to form the magnetostatic wave element. The magnetostatic wave element obtained in this way is mounted on an oscillation circuit employing a common base emitter coupling transistor (TR) 2. Then a DC bias magnetic field is applied perpendicularly to the YIG film and its magnitude is changed. In the oscillating frequency characteristic of the magnetostatic wave oscillation circuit, the continuous variable band of the oscillating frequency is 4.0 to 6.5GHz.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to GGG (Gadolinium
Y formed on a non-magnetic substrate such as gallium / garnet)
The present invention relates to a magnetostatic wave oscillation circuit using magnetic spin resonance of a magnetic thin film such as IG (yttrium, iron, garnet), etc., and relates to an oscillation circuit structure for enabling wideband use.

[0002]

2. Description of the Related Art GGG (gadolinium gallium garnet) is used as an oscillation circuit used in a microwave band or the like.
YIG on non-magnetic substrate by liquid phase epitaxial method
(Yttrium / iron / garnet) A thin film is formed, and a magnetostatic wave resonator having a plurality of conductor film electrodes and pad electrodes formed on the thin film is arranged on a conductor plate, and the pad electrode and the lower conductor are arranged. An oscillating circuit has been proposed which is connected and applies a bias magnetic field in the surface direction of the thin film to generate a high frequency electric signal in a region where the magnetostatic wave resonator has an inductive reactance. (See JP-A-63-228802). This ferrimagnetic thin film resonance oscillator circuit has a high resonance characteristic Q in the microwave band, and applies a DC bias magnetic field to the ferrimagnetic thin film magnetically coupled to the microwave transmission line (such as an electrode finger formed by an etching method). It is characterized in that the resonance frequency can be varied depending on its magnetic field strength.

[0003]

However, when the oscillation frequency characteristic of the magnetostatic wave oscillation circuit is measured by changing the DC bias magnetic field, the oscillation frequency often shows discontinuity at a certain magnetic field strength. there were. Therefore, there is a problem that the continuously variable frequency bandwidth becomes narrow. Therefore, an object of the present invention is to increase the interval at which the discontinuity point of the oscillation frequency is generated so that the oscillation frequency can be continuously swept in a wide band, and to improve the deterioration of the oscillation characteristic of the magnetostatic wave oscillation circuit. It is to provide a magnetostatic wave oscillation circuit having.

[0004]

According to the present invention, a medium in which a magnetostatic wave propagates is formed on one main surface of a non-magnetic substrate, and a plurality of conductor film electrode fingers and pad electrodes are formed on the medium. In a magnetostatic wave oscillation circuit in which a magnetic wave resonator is arranged on a conductor plate and a bias magnetic field is applied in a direction orthogonal to the medium to oscillate, the base terminal of the transistor is grounded, and the magnetostatic wave element is coupled to the emitter terminal. (Hereinafter referred to as grounded-base emitter coupling) is a magnetostatic wave oscillation circuit. Furthermore, in the present invention, the transistor is not limited to bipolar, and HEMT (high-speed electron transfer transistor), FET (field effect transistor), and SIT (static induction transistor) can also be used. In this case, the magnetostatic wave oscillation circuit is one in which the gate terminal of the transistor is grounded and the magnetostatic wave element is coupled to the source terminal (hereinafter referred to as gate ground source coupling). In the present invention, a ferrimagnetic thin film may be formed on a non-magnetic substrate, an electrode may be formed on the ferrimagnetic thin film, and the structure may be such that a magnetostatic wave is excited and propagated in the ferrimagnetic thin film by the electrode, or A structure may be adopted in which a ferrimagnetic thin film is formed on the first nonmagnetic substrate and a magnetostatic wave is excited and propagated in the ferrimagnetic thin film by the electrodes formed on the second nonmagnetic substrate.

[0005]

As a result of detailed analysis of the conventional oscillation circuit, the present inventor has found that the problem is due to the use of the base-grounded collector coupling as the transistor. Further details will be described. The complex reflectance of the transistor (2SC3587) alone is measured by the collector-emitter voltage: V
constant at ce = 6V, collector-emitter current: Ice
= 3, 4, 5 mA and Ice = 4 mA, V
The results measured for cE = 4, 6, and 8 V are shown in FIGS. 2 and 3, respectively. 2 and 3, (a) shows the case where the base-grounded emitter is coupled, and (b) shows the case where the base-grounded collector is coupled. 2B and FIG.
In the case of the base-grounded collector coupling shown in (b), the gain is large and the phase circumference is not so large, and thus phase matching is possible, but the characteristic change is small even if Vce and Ice are changed, and the adjustment of the matching condition requires resonance. It turns out that it is necessary to do it on the circuit side. On the other hand, FIG. 2A and FIG.
In the case of the grounded-grounded emitter coupling shown in (a), the gain in the negative resistance region is slightly small, but the phase rotation is not so large and the negative resistance characteristic largely changes depending on Ice. It is considered that this can be easily performed on the oscillator circuit side and the frequency range in which phase matching can be performed can be widened.

[0006]

EXAMPLES The present invention will be described in detail below with reference to examples. (Embodiment 1) FIG. 1 shows an embodiment of the present invention. The method of manufacturing the magnetostatic wave resonator 1 is as follows. That is, a YIG film having a thickness of about 40 μm was formed on one main surface of the GGG single crystal substrate by the liquid phase epitaxial growth method. Next, an Au film having a thickness of 1.5 μm was formed on the YIG film by an ion plating method, and the Au film was partially removed by a photo-etching method to form five electrode fingers having a width of 30 μm and a length of 3 mm. And pad electrodes were formed on both sides thereof. Then, using a dicer equipped with a diamond blade, the length is 5 mm and the width is 2 m.
A magnetostatic wave resonator 1 having a thickness of 0.5 mm and a thickness of 0.5 mm was cut out from the wafer. A gap larger than the length of the magnetostatic wave resonator 1 is formed by etching in a microstrip line having a structure in which a dielectric is sandwiched between conductor plates on both sides, and a copper conductor plate serving as a connection end to a negative resistance circuit A thickness (l) and width (w) impedance matching stub was prepared. An epoxy resin adhesive was applied to the other main surface of the magnetostatic wave resonator 1 opposite to the one main surface of the GGG single crystal substrate on which the YIG film was formed.
A magnetostatic wave device was produced by applying a coating of 0 μm and fixing the resonator in this gap, soldering the pad electrode and the conductor plate with a copper connecting plate, and the pad electrode and the stub with a copper connecting plate. The magnetostatic wave device thus obtained was mounted in an oscillation circuit using a transistor (2SC3587) 2 forming a base-grounded emitter coupling shown in FIG.
Then, a DC bias magnetic field was applied perpendicularly to the surface of the YIG film, its magnitude was changed, and the oscillation frequency characteristic of this magnetostatic wave oscillation circuit was measured by a spectrum analyzer. The continuous variable band of the oscillation frequency was 4.0. ~ 6.5 GHz
Became. (Comparative Example) A magnetostatic wave resonator manufactured in the same manner as the magnetostatic wave resonator 1 shown in Example 1 was prepared, and the transistor was mounted on an oscillation circuit formed by conventional base-grounded collector coupling.
A DC bias magnetic field was applied perpendicularly to the surface of the YIG film, its magnitude was changed, and the oscillation frequency characteristic of this magnetostatic wave oscillation circuit was measured by a spectrum analyzer. The continuous variable band of the oscillation frequency was 4.7 to 6. It became 0.0 GHz. (Example 2) A 9 GHz band oscillation circuit was formed by using a transistor as a HEMT, and the effect of the present invention was similarly confirmed.

[0007]

According to the present invention, in a magnetostatic wave oscillation circuit in which a medium through which a magnetostatic wave propagates is formed on one main surface of a non-magnetic substrate, the interval at which the discontinuity of the oscillation frequency occurs is increased. It is possible to continuously sweep the oscillation frequency in a wide band,
It is possible to improve the deterioration of the oscillation characteristics of the magnetostatic wave oscillation circuit.

[Brief description of drawings]

FIG. 1 is a structural diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing measurement results of complex reflectance of transistor characteristics. (A) is a figure of the present invention, (b) is a figure showing a conventional thing.

FIG. 3 is a diagram showing measurement results of complex reflectance of transistor characteristics. (A) is a figure of the present invention, (b) is a figure showing a conventional thing.

[Explanation of symbols]

 1 Magnetostatic wave resonator 2 Transistor

Claims (4)

[Claims] 1. A magnetostatic wave oscillation circuit having a medium on which a magnetostatic wave propagates on one main surface of a non-magnetic substrate and a means for exciting the magnetostatic wave by a microwave, and applying a bias magnetic field to the medium to oscillate. 2. A magnetostatic wave oscillation circuit according to claim 1, wherein the base terminal of the transistor is grounded, and the means is coupled to the emitter terminal. 2. A magnetostatic wave oscillation circuit having a medium on which a magnetostatic wave propagates on one main surface of a non-magnetic substrate and a means for exciting the magnetostatic wave by a microwave, and applying a bias magnetic field to the medium to oscillate. 2. A magnetostatic wave oscillation circuit according to claim 2, wherein the gate terminal of the transistor is grounded and the source terminal is coupled to the means. 3. The method according to claim 1, wherein as a means for exciting the magnetostatic wave, a method of flowing a microwave current through a plurality of conductor film electrodes formed on the medium is used. Magnetostatic wave oscillator circuit. 4. The magnetostatic wave oscillation circuit according to claim 1 or 2, wherein a plurality of conductor electrodes formed on a microstrip line are used as means for exciting the magnetostatic wave.