JPH07112121B2 - Microwave equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a microwave device including a magnetostatic wave element that utilizes a ferromagnetic resonance phenomenon of a ferrimagnetic material as a main component.

"Prior art" As a main component used in microwave oscillators, etc., a spherical sample of YIG (yttrium, iron, garnet) single crystal produced by the flux method, or on a GGG (gadolinium, gallium, garnet) substrate , A magnetostatic wave device using a ferrimagnetic material such as a liquid phase epitaxially grown YIG thin film has been proposed.

FIG. 2 is a schematic configuration diagram of a magnetostatic wave resonator 1 showing an example of a conventional technique using a magnetostatic wave element 1a made of a YIG thin film. In this figure, the magnetostatic wave device 1a is composed of a YIG thin film 23 grown on the GGG substrate 22 by a liquid phase epitaxial method.
A plurality of electrode fingers 24 made of a gold or aluminum film on the thin film 23 and pad electrodes 25a, 2 on both sides of the electrode fingers 24.
5b is formed by photolithography technology. The pad electrode 25b is connected to the ground conductor 26 of the microwave circuit by the conductor Wb, and Wa1 and Wa2 serve as input terminals of the microwave circuit. These serve as a coupling means between the magnetostatic wave element 1a and the microwave circuit, and the magnetostatic wave resonator 1 is formed.

At this time, when a magnetic field Ho is applied perpendicularly to the film surface of the YIG thin film 23, a magnetostatic forward volume wave is applied to the magnetostatic wave element 1a by i in the figure.
It propagates in the direction and resonates due to the reflection from the end face.
Since the frequency at which the resonance occurs can be changed by the applied magnetic field Ho, the magnetostatic wave resonator 1 can form a frequency variable microwave device.
Magnetostatic wave element 1a has high selectivity (Q) due to high quality YIG thin film
It is disclosed that it has excellent characteristics such as having a large variable width of the resonance frequency. It is also disclosed that the device can be manufactured at a relatively low cost because the device is manufactured by photolithography, as compared with a device using a YIG sphere that is already widely used in the microwave region.

In order to fabricate a practical microwave device using such a magnetostatic wave element, the applied magnetic field is changed by the current flowing through the coil, and the resonance frequency of the magnetostatic wave element is controlled according to the frequency width used. How to do it is well known.

In this case, in order to stabilize the frequency, a PLL control method as shown in FIG. 6 in which the microwave output is fed back to the coil is often adopted. Here, 42 is a microwave oscillator using a magnetostatic wave element, 43 is a frequency divider, 44 is a phase detector, 45 is a reference frequency source, and 41 is a coil drive circuit.

The coil is usually composed of two types of coils, a main control coil and a fine adjustment control coil. In this case, a method is used in which a current corresponding to the oscillation frequency is made to flow in the main control coil in advance and a current corresponding to the PLL control signal is made to flow in the fine adjustment control coil. At this time, since the fine adjustment control coil needs a quicker response than the main control coil, it is customary to use a coil having a small number of turns and a small magnetomotive force.

"Problems to be Solved by the Invention" However, the above-described configuration has the following problems. For example, when the operating temperature range changes from room temperature to high temperature or low temperature, the center frequency due to the current of the main control coil given in advance largely deviates from the desired frequency due to the temperature characteristic of the microwave device. If this amount is to be compensated by the fine adjustment control coil, the magnetomotive force of the fine adjustment control coil must be designed to be sufficiently large. As a result, there is a problem that the response speed is lowered or the power consumption is increased. Therefore, if a fast response is required, the frequency variable range (dynamic range) of the fine adjustment control coil will necessarily be small.

First, an example of the prior art will be described. FIG. 5 is a diagram of a coil driver according to the prior art. The two coils of the microwave oscillator 53, the main control coil 7a and the fine adjustment control coil 7b are respectively driven by independent coil driving units 52 and 51.

First, using only the drive circuit 52 of the main control coil 7a,
It was incorporated into the PLL loop in the figure and operated. This corresponds to using 52 and 53 in FIG. 5 instead of 41 and 42 in FIG. As a result, unexpectedly large hunting occurred and stable PLL control was impossible.

Next, a bias current was given to the main control coil 7a from the drive power source 52 by initiative, and the drive circuit 51 of the fine adjustment control coil 7b was used to similarly incorporate and operate in the PLL loop of FIG. This corresponds to using 51 and 53 in FIG. 5 instead of 41 and 42 in FIG. In this case, stable
PLL control was possible. However, it was not possible to follow the frequency determined by the bias current of the main control coil 7b in the range of about 20 MHz.

In view of the above problems, an object of the present invention is to adjust the current of the main control coil so that the operating point of the control coil for fine adjustment is always kept at the center of the variable bandwidth, thereby providing a quick response and low power consumption. It is to provide a microwave device using a magnetic wave element.

"Means for Solving the Problem" A microwave device of the present invention is a magnetostatic wave element using a ferrimagnetic material, a coupling means for coupling the magnetostatic wave element and a microwave circuit, and a magnetic field to the magnetostatic wave element. A microwave device comprising: a magnetic field applying means for applying a magnetic field; and a means including at least two coils as the magnetic field applying means, for detecting a microwave output of the microwave circuit and feeding back to a drive signal of the coil. The drive signal of at least one of the two coils includes an integrated signal of drive signals of the other coils.

As an example of the microwave device, in the case of a microwave oscillator using a magnetostatic wave element, a function of stabilizing the oscillation frequency against the ambient temperature and other factors by PLL control will be considered. Actually stabilizing the oscillation frequency by PLL control shows that the variable frequency width required for feedback requires a large amount of feedback for low-frequency fluctuation components and for high-frequency fluctuation components. The inventors have found that a small amount of feedback is required.

For example, a change in frequency due to a change in ambient temperature requires an extremely large amount of time from the change in temperature to the actual change in oscillation frequency due to the large heat capacity of the case, magnetic circuit, etc. However, the amount of change eventually becomes large.

On the other hand, a relatively fast noise component due to induction from a commercial power source has a relatively small frequency fluctuation range in an actual use state. When controlling with the fine adjustment control coil, both a fast response and a large magnetomotive force are required to simultaneously satisfy both the speed responding to high frequency components and the wide dynamic range corresponding to slow components. Therefore, the coil is designed to have as large a current as possible with a minimum number of turns.

Further, the main control coil normally generates a magnetomotive force satisfying a required frequency variable bandwidth with appropriate power consumption by increasing the number of windings. For this reason, the response is slower than that of the fine adjustment control coil, but it is possible to control the slow component. That is, by extracting only the slow component of the control signal of the fine adjustment control coil and feeding it back to the main control coil, a control system having a substantially wide dynamic range and a fast response can be realized.

In such a configuration, the current flowing through the fine adjustment control coil eventually becomes almost zero for normal operation, which has a secondary effect of reducing power consumption.

[Embodiment] FIG. 4 is a structural cross-sectional view of a microwave oscillator which is the basis for carrying out the embodiment of the present invention. Reference numeral 1 is a magnetostatic wave resonator using a YIG thin film, which is installed on a printed board 2. The magnetostatic wave resonator 1 includes a main control coil 7a, a fine adjustment control coil 7b, and a rare earth magnet 4
A magnetic field is applied perpendicular to the YIG film surface. This magnetostatic wave resonator 1 changes the winding currents of two coils,
It is designed to resonate in a wide range of 4.5 to 6.0 GHz.

In the figure, 3 is a shield plate made of copper, 4 is a rare earth magnet, 5 is a first magnetic pole, 6 is a second magnetic pole, 7a is a main control coil, 7b is a fine adjustment control coil, 8 is a first yoke, and 9 is a first Reference numerals 2 and 10 are joint portions of the first yoke and the second yoke.

The microwave circuit formed on the printed circuit board 2 has a third
As shown, transistor 34, coupling capacitor 33
And a negative resistance circuit composed of other components, and functions as a magnetostatic wave resonator 1 as a microwave oscillator. Reference numeral 31 is a terminal for supplying a DC voltage to the transistor 34, and 32 is an output terminal for microwaves. Reference numeral 35 is a microwave blocking inductor that prevents microwaves from flowing into the DC power supply side.

The effects of the present invention will be described in detail below with reference to examples.

Example 1 FIG. 1 is a diagram showing an example of the present invention. In the figure, 53 is a microwave oscillator having the same structure as in FIG. 4, 51 is a drive circuit for the fine adjustment control coil, 54 is an integration circuit, and 52 is a drive circuit for the main control coil. The output of the drive circuit 52 for the main control coil is connected to the main control coil 7a shown in FIG. 4, and the output of the drive circuit 51 for the fine adjustment control coil is connected to the fine control coil 7b shown in FIG. Fine adjustment control coil drive circuit 51
The output voltage of is integrated by the integration circuit 54 and becomes the input of the drive circuit 52 of the main control coil.

When the circuit of FIG. 1 of the present embodiment is incorporated and operated in place of 41 and 53 in the block diagram of the PLL loop of FIG. 6, 4.
PLL control could be performed stably over the entire frequency band of 5 to 6.0 GHz.

In the prior art of FIG. 5, the PLL control range is only 20 MHz.
On the other hand, in the present embodiment of the present invention, the control range is remarkably wide at about 1.5 GHz, which shows that the structure of the present invention is excellent.

(Embodiment 2) FIG. 7 is a view showing another embodiment of the present invention. The drive circuit 52 for the main control coil is the drive circuit 51 for the control coil for fine adjustment.
The difference from the first embodiment is that the input signal is connected via an integrating circuit 54. Also in this embodiment, Embodiment 1
Similar results were obtained.

In the present invention, as the integrating circuit, a known one (for example, "Basics of sensors and their applications", Morikita Shuppan, p.25, 1985) can be used.

Incidentally, as the embodiment here, only the YIG thin film was described, but the scope of the present invention in which the drive signal of the main control coil is an integrated signal of the drive signal of the fine adjustment control coil is limited to this. Rather, it can be easily understood by a person skilled in the field of the present invention that it can be applied to other magnetostatic wave elements using the ferromagnetic resonance phenomenon of a ferrimagnetic material, for example, a microwave device using a YIG sphere. is there.

[Advantages of the Invention] According to the technique of the present invention, it is possible to realize a frequency variable microwave device capable of high-speed feedback over a wider dynamic range than that of the conventional technique, and to provide a microwave oscillator, a filter, a delay line, or the like. It can be used effectively.

[Brief description of drawings]

1 and 7 are circuit block diagrams showing an embodiment of the present invention, FIG. 2 is a schematic configuration diagram of a conventional magnetostatic wave resonator, and FIG. 3 is a circuit diagram of a conventional microwave oscillator. FIG. 4 is a schematic structural sectional view of a microwave device of the prior art, FIG.
FIG. 6 is a circuit block diagram of the prior art. 1: Magnetostatic wave resonator 1a: Magnetostatic wave element, 22: GGG substrate, 23: YIG thin film 4: Rare earth magnet, 5, 6: Magnetic pole, 7a: Main control coil, 7b: Control coil for fine adjustment, 8, 9: Yoke, 41: Coil drive circuit, 42: Microwave oscillator, 43: Frequency divider, 44: Phase detector, 45: Reference frequency source, 51: Fine adjustment control coil drive circuit, 52: Main control coil drive circuit, 53: microwave oscillator, 54: integrating circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H03L 7/099 (56) References JP-A-1-140803 (JP, A) JP-A-1- 191504 (JP, A) JP 62-281610 (JP, A) JP 61-296276 (JP, A) JP 63-84301 (JP, A) JP 63-296414 (JP, A) 3-20516 (JP, U) 1-162917 (JP, U) 1-162917 (JP, U) 1989 IEICE Autumn National Convention SC-9-6

Claims (1)

[Claims] 1. A magnetostatic wave element using a ferrimagnetic material, coupling means for coupling the magnetostatic wave element and a microwave circuit, magnetic field applying means for applying a magnetic field to the magnetostatic wave element, and magnetic field applying means. A microwave device including at least two coils, and means for detecting a microwave output of the microwave circuit and feeding back to a drive signal of the coil, at least one coil among the at least two coils is provided. A microwave device, wherein the drive signal includes an integrated signal of drive signals of other coils.