JP2523600B2 - Magnetostatic wave oscillator - Google Patents

Description

The present invention relates to a variable frequency magnetostatic wave oscillator using YIG magnetic spin resonance, and in particular, it is composed of a YIG / GGG magnetostatic wave chip resonator and a transistor stone. The present invention relates to an integrated oscillator circuit which has a simple basic circuit configuration and is suitable for miniaturization and power saving.

[Conventional technology]

The conventional device is "IEE 19".
84 Ultrasonic Symposium
posium) PP.152-163 ”(Fig. 2), 2
A variable oscillator has been discussed in which a magnetostatic wave delay line composed of a single transducer 6 and a YIG / GGG substrate 7 is added to a positive feedback loop from an output terminal to an input terminal of a high-frequency amplifier 8 having three stages of CaAs-FETs.

[Problems to be solved by the invention]

The above-mentioned prior art does not consider the simplification of the oscillation circuit and the reduction in size and power consumption. Since a large number of expensive high frequency elements and parts are used, the substrate area of the oscillation circuit becomes large and the power consumption also becomes large. There was a problem. In addition, there was a problem that the magnetostatic wave delay line was 10 mm or more. Accordingly, the magnetic pole of the electromagnet that applies the bias magnetic field is also large in size of 2.5 inches × 2.5 inches × 2 inches.

An object of the present invention is to reduce the size of an oscillator and save power by using a small two-terminal magnetostatic wave resonator having a chip length of about 2 mm and a simple basic oscillation circuit connected to two of the three terminals of a transistor. It is in.

[Means for solving problems]

The above object is to realize a magnetostatic wave two-terminal resonator, which is used as a crystal resonator in a crystal oscillator circuit.
This is achieved by connecting to two of the terminals and connecting the remaining one terminal and the two terminals with a capacitive or inductive reactance.

That is, as shown in FIG. 1, it is achieved by connecting the two-terminal magnetostatic wave resonator 1 to the two terminals of the transistor 2 and connecting the capacitors 3 and 5 or the inductive reactance 4 between the other terminal and the two terminals. It 1 (a) is known as a Colpitts type oscillation circuit, and FIG. 1 (b) is known as a Hartley type oscillation circuit. In an actual oscillator circuit, a circuit for supplying DC power is added to the basic circuit shown in FIG.

The broadband magnetostatic wave variable resonator 1 is used as a 2-terminal resonator having only an input terminal by short-circuiting the output terminals of a 4-terminal resonator. A small cylindrical magnet having a diameter of about 20 mm is used as the small magnet.

[Action]

The oscillating circuit of FIG. 1 can oscillate at a frequency where the impedance of the magnetostatic wave resonator 1 is an inductive reactance and matches the capacitive reactance of the input impedance seen from the transistor side. The condition for continuing the oscillation is that the resistance component of the impedance of the magnetostatic wave resonator 1 matches the negative resistance of the input impedance, and the DC voltage and current move to the operating point where the dynamic characteristics of the transistor satisfy this condition. Then, the oscillation state is maintained.

In some cases, a temperature compensation circuit may be added to the power supply circuit and a buffer amplifier circuit may be added to the output circuit.
This is also necessary in the prior art shown in the figure, and the simplicity of the basic circuit shown in FIG. 1 is effective for downsizing and power saving.

Further, since the two-terminal magnetostatic wave resonator resonates the magnetostatic wave at the chip end face, it is smaller than the magnetostatic wave delay line shown in FIG. 2, and the magnet for applying the bias magnetic field is also miniaturized.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 3, 4, and 5. In FIG. 3, a circuit for supplying DC power and a circuit for extracting oscillated power are added to the basic circuit of FIG. 1 (a). This is because the electrostatic capacitance 9 does not allow a direct current to flow in the magnetostatic wave resonator 1. However, when the parallel resistance of the resonator 1 is smaller than the negative resistance, the electrostatic capacitance 9 is about the same as the electrostatic capacitances 3 and 5. It is also possible to operate as a clamp type oscillation circuit with a value of. The inductive reactance 10 blocks high-frequency current from flowing into the power supply circuit. FIG. 4 shows an embodiment in which the circuit of FIG. 3 is constructed on an actual microstrip substrate 13. The length of the inductive reactance 10 is shortened by bending a line having a characteristic impedance of about 100Ω into a meandering shape. DC power is supplied from the ground potential of the back conductor of 13 and terminal 11. It is needless to say that the ground potential may use an electrode made conductive by a through hole on the upper surface of 13. The oscillated power is taken from the back conductors of terminals 12 and 13. FIG. 5 shows an example of a two-terminal resonator. A plurality of electrode fingers 16 of an Al film and a pad electrode 17 are formed on a 40 μm-thick YIG film 15 liquid-phase-grown on a GGG substrate 14, and a conductor plate 18 is placed below 14 to form a pad electrode 17. One is wirebonded to 18 and the other is wirebonded to extract the electrical signal. A part of the lower conductor of the microstrip substrate 13 of FIG. 4 may be used as 18. FIG. 4 shows an embodiment in which two terminals of FIG. 5 are taken out as pin electrodes and wire-bonded from 17 to the pin electrodes.
A bias magnetic field Ho is applied in the direction of the electrode fingers to excite magnetostatic surface waves, which are then resonated by being reflected by the chip end faces. When Ho = 4000e is applied to a YIG film with a saturation magnetic field of 4πMs = 17400e, the magnetostatic surface wave wavelength becomes about 4mm at a frequency of about 3GHz, and the chip length is 2mm.
Resonates to mm. When the strength of the applied magnetic field is changed using the drive coil, the resonance frequency is changed while the resonance wavelength remains 4 mm,
Therefore, the oscillation frequency is changed.

FIG. 6 shows the frequency characteristic 19 of the input impedance of the magnetostatic surface wave resonator of FIG. 5 on the Smith diagram when the applied magnetic field Ho = 4000e.

The area of the frequency where the reactance of 19 is positive, that is, 19
Is the frequency in the upper half of the Smith diagram, about 1.5 GHz or more and 2.96
It can oscillate near GHz. The load resistance seen by the oscillator circuit is 1
It oscillates at the frequency that cancels the resistance of 9 and the operating point of the transistor. When the applied magnetic field Ho is directed in the film surface direction perpendicular to the electrode fingers, it becomes an example of a resonator in which a magnetostatic volume backward wave is excited, and is suitable for oscillation at a frequency lower than that of a magnetostatic surface wave. A magnetic field is applied in the film surface direction of YIG15, and a cylindrical magnet is used to form a resonator 1.
Is miniaturized.

Further, the case where the microstrip substrate integrated circuit of FIG. 4 is arranged inside the cylindrical magnet to reduce the size as a whole is also an embodiment of the present invention.

FIG. 7 shows another embodiment of the two-terminal magnetostatic wave resonator.
A bias magnetic field Ho is applied in the film surface direction of YIG1.5 perpendicular to the electrode fingers to excite a magnetostatic volume backward wave, and the electrode fingers 16 are alternately cut off to form an interdigital form. The impedance frequency characteristics 20 when a bias magnetic field of Ho = 4000e is applied are shown on the Smith diagram. It is suitable for oscillation at a lower frequency than the magnetostatic surface wave of 19. Further, the capacitor 9 is unnecessary.

Further, it will be easily understood by a person skilled in the art that the bias magnetic field Ho can be applied perpendicularly to the film surface to excite the magnetostatic forward volume wave.

Another embodiment of the present invention is a case where a two-terminal magnetostatic wave resonator 1 is used in the oscillation circuit of FIGS. 1 (b) and 1 (c). For the inductive reactance 4, the embodiment using the shape of the microstrip line element 10 in FIG. 4 is the simplest, but other types of distributed constant reactance elements may be used, and in FIG. It can also be used for commercial purposes, which blocks high-frequency currents. A DC circuit, an output circuit, a small magnet, etc. are added as in the previous embodiment. Also, replace the transistor with a FET,
The case of changing 4πMs by changing the composition of IG is of course an embodiment of the present invention.

〔The invention's effect〕

According to the present invention, since the oscillation basic circuit can be simplified, there are the following effects.

(1) Compared with the conventional example in which a magnetostatic wave delay line is used for the positive feedback loop, the oscillation basic circuit has a simple circuit configuration that requires only one transistor, and the oscillation circuit can be downsized and power consumption can be reduced.

(2) Compared with the magnetostatic wave delay line, the magnetostatic wave resonator of the present invention is small, and accordingly, the magnet and the drive coil for applying the bias magnetic field are also miniaturized and lightened.

(3) As a result of downsizing the drive coil, the time constant of the coil is reduced and the frequency variable drive speed is increased.

[Brief description of drawings]

FIG. 1 is a wiring diagram of an oscillation basic circuit according to the present invention, FIG. 2 is a basic conceptual diagram of a conventional example, FIG. 3 is a wiring diagram showing an embodiment of the present invention, and FIG. FIG. 5 is an external view of the magnetostatic wave resonator of the present invention, FIG. 6 is a Smith diagram showing impedance frequency characteristics of the resonator of FIG. 5, and FIG. It is an external view which showed the other Example of the magnetic wave resonator. 1 ... Magnetostatic wave resonator, 2 ... Transistor, 3 ... Capacitor, 4 ... Induction reactor, 5 ... Capacitor, 6 ...
… Transducer, 7… Magnetostatic wave delay line chip, 8…
… Capacitor, 10 …… Strip line element, 11 …… Oscillation output terminal, 13 …… Micro strip line substrate, 14 ……
GGG, 15 …… YIG, 16 …… Al film electrode finger, 17 …… pad electrode, 18 …… conductor plate, 19 …… impedance characteristic, 20 ……
Impedance characteristics.

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Sadami Kubota 5200 Mikkajiri, Kumagaya City, Institute for Magnetic Materials, Hitachi Metals Co., Ltd. (56) References JP-A-60-257607 (JP, A) JP-A-62- 245704 (JP, A)

Claims (1)

(57) [Claims] 1. A high-frequency wave by connecting a magnetostatic wave resonator between any two terminals of a base terminal, an emitter terminal, and a collector terminal of a transistor and causing the magnetostatic wave resonator to function as an inductive reactance element. In a magnetostatic wave oscillation circuit configured to generate an electric signal, the magnetostatic wave resonator has a conductor plate electrically connected to one of the two terminals, and a GGG mounted on the conductor plate.
(Gadolinium, gallium, garnet) substrate, YIG (yttrium, iron, garnet) film formed on the surface of the substrate, and formed on the surface of the YIG film facing each other, one of which is electrically Electrically connected and the other electrically connected to the other of the two terminals, and a pair of pad electrodes electrically arranged in parallel with each other between the pad electrodes on the surface of the YIG film. It is composed of at least one of the pad electrodes and a plurality of electrode fingers integrally formed, and is biased in a direction perpendicular to the YIG film or in a direction perpendicular or parallel to the electrode fingers in the plane of the YIG film. A magnetostatic wave oscillation circuit characterized by applying a magnetic field.