# US 4,395,686 A · Attenuation of higher order width modes in magnetostatic wave devices

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- Number: US 4,395,686 A
- Document ID: US4395686A
- Status: Granted
- Kind: A
- Application number: 06/308,011
- Filed: 1981-10-02
- Granted: 1983-07-26
- Earliest claimed: 1981-10-02
- Assignees: Westinghouse Electric Corp.
- Inventors: John D. Adam
- Web page: https://patentgrep.com/patent/US4395686A

## CPC

- H03H 2/001: {comprising magnetostatic wave network elements}
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)

## Abstract

A magnetostatic wave device is described incorporating a plurality of resistive strips spaced apart from one another and transverse to the propagation path of magnetostatic waves in a material such as a YIG film having a finite width for attenuating selected higher order modes of propagating magnetostatic waves.

## Claims

### Claim 1

A magnetostatic wave device operable with microwave signals and operable within a biasing magnetic field, comprising:
material suitable for propagating magnetostatic waves in a first direction and having a finite width transverse to said first direction;
a first and second transducer located in spaced apart relationship in association with said material for generating and receiving magnetostatic waves along a propagation path therebetween in said first direction; and
a plurality of resistive strips spaced apart from one another and positioned above said material and transverse to said propagation path for attenuating selected modes of propagating magnetostatic waves occurring due to said finite width of said material.

### Claim 2

A mode filter for attenuating selected higher order modes in a magnetostatic wave device utilizing a suitable material for propagating magnetostatic waves along a path comprising:
a plurality of resistive strips spaced apart from one another and positioned on said material transverse to said path.

### Claim 3 (depends on 1, 2)

The magnetostatic wave device of claim 1 or 2 wherein said plurality of resistive strips include aluminum having a thickness in the range from 10 to 400 Angstroms.

### Claim 4 (depends on 1, 2)

The magnetostatic wave device of claim 1 or 2 wherein said plurality of resistive strips are positioned parallel to one another.

### Claim 5 (depends on 1, 2)

The magnetostatic wave device of claim 1 or 2 wherein said resistive strips are spaced apart from one another by a predetermined distance.

### Claim 6 (depends on 1, 2)

The magnetostatic wave device of claim 1 or 2 wherein said resistive strips are rectangular in shape having a predetermined length.

### Claim 7 (depends on 1, 2)

The magnetostatic wave device of claim 1 or 2 wherein said resistive strips are rectangular in shape having a predetermined width.

### Claim 8 (depends on 1, 2)

The magnetostatic wave device of claim 1 or 2 wherein at least one of said resistive strips has a plurality of segments colinear to one another.

### Claim 9 (depends on 1, 2)

The magnetostatic wave device of claim 1 or 2 wherein at least one of said resistive strips has a plurality of segments of equal length colinear to one another.

### Claim 10 (depends on 1, 2)

The magnetostatic wave device of claim 1 or 2 wherein said plurality of resistive strips extend across the entire width of said material.

### Claim 11 (depends on 1, 2)

The magnetostatic wave device of claim 1 or 2 wherein said plurality of resistive strips each have a resistivity of at least 1 ohm/square centimeter.

### Claim 12 (depends on 1, 2)

The magnetostatic wave device of claim 1 or 2 wherein said material is yttrium iron garnet.

### Claim 13 (depends on 1, 2)

The magnetostatic wave device of claim 1 or 2 wherein said plurality of resistive strips include chromium.

### Claim 14

Apparatus for delaying microwave signals comprising:
a substrate of gadolinium gallium garnet having a first surface;
a film of yttrium iron garnet deposited on said first surface;
first means for generating magnetostatic waves in said film in response to said microwave signals;
second means for converting magnetostatic waves propagating in said film to microwave signals;
and, third means for attenuating magnetostatic waves of higher order modes traveling transverse to the direction between said first and second means.

### Claim 15 (depends on 14)

The apparatus of claim 14 wherein said third means for attenuating include conductive electrodes spaced apart from one another and positioned on said film transverse to the direction between said first and second means.

### Claim 16 (depends on 15)

The apparatus of claim 15 wherein said conductive electrodes have a first and second end and have a predetermined resistance from its first to second end.

### Claim 17 (depends on 14)

The apparatus of claim 14 wherein said third means for attenuating include a transverse grating formed longitudinally on the surface of said film intermediate said first and second means.