JPH03126301A - Magnetostatic wave device - Google Patents

Abstract

PURPOSE:To obtain a magnetostatic wave device with a low insertion loss, excellent harmonic mode suppression ratio and a wide pass band width by providing plural ferrimagnetic bases narrow in width and each separated by the intervals in the width direction and input and output transducers in a way of crossing the plural ferrimagnetic bases. CONSTITUTION:YIG thin films 14 as ferrimagnetic bases are formed to one major face of a GGG base 12 and separated by the equal intervals in the width direction and an input parallel strip transducer 16 is provided in a way of crossing one end of each YIG thin film 14. Thus, when a DC magnetic field is applied in a direction orthogonal to the major side of the YIG thin film 14 and a signal is inputted to the input transducer 16, a magnetostatic forward volume wave is stimulated by an electromagnetic wave or the like generated from a strip line 16a and received by a strip line 18a of an output transducer 18 and outputted as a signal. Thus, a magnetostatic wave device width a low insertion loss, excellent harmonic mode suppression ratio and a wide pass band width is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetostatic wave device, and more particularly to a magnetostatic wave device that has a ferrimagnetic substrate such as a YIG thin film and is used, for example, as a filter.

(Prior art) Conventional magnetostatic wave filters that form the background of this invention include Y,
J, Ataiiiyan and J, M, Owens
1986 IEEE MTT-S Dig by et al.
EST, P, P, 575-57B, there is a device in which a transducer is provided on one YIG element and the structure of the transducer is devised to control the passband width.

Also, in 1988 IE by J. D. Adam et al.
EE MTT-SDigest P, P, 879-8
82, there is a magnetostatic wave filter in which one filter bank is constructed using a plurality of YIG elements.

Furthermore, P, P, 153~ of the 1989 IEEE MTT-3 Digest by T, NiN15hika et al.
156, a magnetostatic wave filter in which the passband width was controlled by controlling the thickness of the YIG thin film, and T,
As announced in the proceedings of the 1989 Autumn National Conference of the Institute of Electronics, Information and Communication Engineers, by NiN15hika et al.
There is a magnetostatic wave filter in which the passband width is controlled by controlling the width of the cm film.

(Problem to be Solved by the Invention) However, all conventional magnetostatic wave filters have a low insertion loss of, for example, 3 dB or less, an excellent high-order mode suppression ratio of, for example, 50 dB, and a passband of, for example, 27 MHz at 3 dB. However, it has not been possible to simultaneously satisfy a wide passband width.

Therefore, the main objective of this invention is to achieve low insertion loss and
It is an object of the present invention to provide a magnetostatic wave device having an excellent higher-order mode suppression ratio and a wide passband width.

(Means for Solving the Problems) The present invention includes a plurality of narrow ferrimagnetic substrates provided at intervals in the width direction, and an input/output device provided across the plurality of ferrimagnetic substrates. It is a magnetostatic wave device including a transducer.

(Function) Even if the width of the ferrimagnetic substrate is narrowed, the insertion loss does not increase so much, and higher-order modes are suppressed.

Furthermore, since a plurality of ferrimagnetic substrates are used, the passband width is widened.

(Effects of the Invention) According to the present invention, a magnetostatic wave device with low insertion loss, excellent high-order mode suppression ratio, and wide passband width can be obtained.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

(Embodiment) FIG. 1A is a plan view of a main part showing an embodiment of the present invention, and FIG. 1B is a side view thereof.

This magnetostatic wave device 10 has, for example, five 000 units as a stand.
5 bodies 12, 12. ··including. These GGG bases 12 are each formed to have a length of 20 squares, 2 widths, and 1 layer, respectively, and are arranged at equal intervals in the width direction.

Further, on one main surface of each of these GGG substrates 12, a YIGi film 14 as a ferrimagnetic substrate is formed. Note that each of these YIG thin films 14 is formed to have, for example, a length of 20 mm, a width of 1 am, and a thickness of 113 μm. Therefore, these YIG thin films 1
4 are arranged at equal intervals in the width direction.

Each GGG substrate 12 and Y in this example
The IG thin film 14 is formed, for example, by growing YIG on one main surface of a plate-shaped GGG substrate by liquid phase epitaxial (LPE) and cutting it.

Further, a parallel strip transducer 16 for input is provided across one end of each YIG thin film 14. In this embodiment, the transducer 16 is
It includes, for example, five elongated strip lines 16a, 15a, . . . provided at intervals in the width direction, and these strip lines 16a each
4 is placed across one end of the 4.

Similarly, for example, five strip lines 18a, 11
An output parallel strip transducer 18 having 3a, . . . is provided across the other end of each YIGI film 14.

This magnetostatic wave device IO includes, for example, a Y I G thin film 14.
A direct current magnetic field is applied in a direction perpendicular to the main surface of. In this state, if a signal is input to the input transducer 16, the strip line 1 of that transducer 16
A volumetric forward magnetostatic wave (MSFVW) is excited by electromagnetic waves generated from 6a. Further, this volumetric forward magnetostatic wave is propagated on each YIG thin film 14 toward the output transducer 18 side. Then, the volumetric forward magnetostatic wave is transmitted to the strip line 18a of the output transducer 18.
The signal is received by the transducer 18 and output as a signal.

In this embodiment, since the width of the YIG thin film 14 is narrow, the suppression ratio of higher-order modes is increased. Furthermore, YIG thin film 14
The film thickness is 113 μm, which is sufficient to improve insertion loss, resulting in low insertion loss.

Moreover, in this embodiment, a plurality of 14 YIGI films 4
The passband width is also widened.

That is, the frequency characteristics of this magnetostatic wave device 10 are shown in FIG. 2, and compared to this magnetostatic wave device 10, the YIG thin film 14
The frequency characteristics of the magnetostatic wave device, which is the only one installed, are
As shown in the figure, in this magnetostatic wave device 1O, compared to a magnetostatic wave device in which only one YIG thin film 14 is provided,
Its pass band is wide.

FIG. 4A is a plan view of a main part showing a modification of the embodiment shown in FIGS. 1A and 1B, and FIG. 4B is a side view thereof.

In this embodiment, five YIG thin films 14 are formed on one main surface of one plate-shaped 0005 body 12 at equal intervals in the width direction, compared to the embodiment shown in FIGS. 1A and 1B. has been done. The YIG thin film 14 in this example is:
For example, YrG can be grown on one main surface of the GGG substrate 12 and formed by etching.

Similarly to the embodiments shown in FIGS. 1A and 1B, this embodiment also has a low insertion loss, an excellent suppression ratio of higher-order modes, and a wide passband width.

In each of the above embodiments, the five YIG thin films 14 are formed to have the same width and are arranged at equal intervals, but the widths of the YIG thin films 14 are formed to have different widths. The YIG thin films 14 may also be arranged at different intervals. Furthermore, the number and thickness of YIG thin Jli 14 may be changed arbitrarily.

Further, in each of the above-described embodiments, parallel strip transducers are used as transducers, but transducers of other shapes may be used in the present invention.

Furthermore, the direction of the DC magnetic field applied to the YIGi film 14 is
It may be changed arbitrarily. For example, a magnetic field may be applied in a direction parallel to the main surface of the YIG thin film 14 and perpendicular to the propagation direction of the magnetostatic wave. In this case, a surface magnetostatic wave (MSSW) is propagated on the YIG thin film I4. or,
A magnetic field may be applied in a direction parallel to the main surface of the YIG thin film 14 and parallel to the propagation direction of the magnetostatic waves. In this case, YIG
A volume-backward magnetostatic wave (MSBVW) is propagated through the thin film 14 .

[Brief explanation of the drawing]

FIG. 1A is a plan view of essential parts showing an embodiment of the present invention, and FIG. 1B is a side view thereof. FIG. 2 is a graph showing the frequency characteristics of the embodiment shown in FIGS. 1A and 1B. FIG. 3 is a graph showing the frequency characteristics of a magnetostatic wave device provided with only one YIG thin film. FIG. 4A is a plan view of a main part showing a modification of the embodiment shown in FIGS. 1A and 1B, and FIG. 4B is a side view thereof. In the figure, 10 is a magnetostatic wave device, 14 is a YIG thin film, 1
6 and 18 indicate transducers. Figure 1A

Claims (1)

[Claims] A magnetostatic wave comprising a plurality of narrow ferrimagnetic substrates provided at intervals in the width direction, and an input/output transducer provided across the plurality of ferrimagnetic substrates. Device.