US4878036A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Surface elastic wave filter
Assignee: Nihon Musen KK
•
Filing: 1987-07-15
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Granted: 1989-10-31
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Expires: 2007-07-15
Abstract
Abstract A surface elastic wave filter has a pair of electrodes on a surface of a piezoelectric body, and at least one of the electrodes is constructed as electrode fingers in the form of comb teeth which are progressively spread away from each other along a direction normal to the direction in which a surface elastic wave is propagated on the surface of the piezoelectric body. A grating or dot structure as a scattering reflector for scattering and reflecting a portion of the surface elastic wave is disposed in a desired position between the electrodes. Alternatively, some of electrode fingers of a surface elastic wave filter are dropped or removed, or divided voltages are applied to electrode fingers, or a scattering reflector is added to a filter with some of its electrode fingers removed or with divided voltages applied to electrode fingers. With such an arrangement, a filter having good selectivity and desired frequency characteristics can be achieved.
Inventors
- 👤 Hiromi Yatsuda
- 👤 Yoshihiko Takeuchi
- 👤 Toichi Kohda
- 👤 Shokichiro Yoshikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 10:47
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/02; H03H9/02535; H03H9/02637; H03H9/02685; H03H9/02771; H03H9/02645; H03H9/125; H03H9/145; H03H9/14544; H03H9/14547; H03H9/14558; H03H9/46; H03H9/64; H03H9/6423; H03H9/14517; H03H9/14526
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
77 words
A surface elastic wave filter comprising: a piezoelectric body having a surface; a pair of electrodes disposed on said surface for sending and receiving a surface elastic wave between said electrodes to pick up a signal of prescribed frequency bandwidth characteristics, at least one of said electrodes comprising a plurality of splayed electrode fingers; and a structure disposed on said surface between said electrodes for scattering and reflecting surface elastic waves having prescribed frequencies within said bandwidth.
Claim 2
Dependent Claim
77 words
A surface elastic wave filter comprising: a piezoelectric body having a surface; a pair of electrodes disposed on said surface for sending and receiving a surface elastic wave between said electrodes to pick up a signal of prescribed frequency bandwidth characteristics, at least one of said electrodes comprising a plurality of splayed electrode fingers; and a structure disposed on said surface between said electrodes for scattering and reflecting surface elastic waves having prescribed frequencies within said bandwidth.
Claim 3
Dependent Claim
16 words
A surface elastic wave filter according to claim 1 wherein said structure comprises a grating structure.
Claim 4
Dependent Claim
16 words
A surface elastic wave filter according to claim 1, wherein said structure comprises a dot structure.
Claim 5
Dependent Claim
42 words
A surface elastic wave filter according to claim 3, wherein said dot structure comprises a plurality of dots spaced at a constant spacing and arranged at a pitch equal to a multiple of 1/2 of the wavelength of the surface elastic wave.
Claim 6
Dependent Claim
37 words
A surface elastic wave filter according to any one of claims 1 through 4, wherein said structure is inclined from a direction normal to the direction in which the surface elastic wave is propagated between said electrodes.
Claim 7
Dependent Claim
96 words
A surface elastic wave filter comprising: a piezoelectric body having a surface; a pair of electrodes disposed on said surface for sending and receiving a surface elastic wave between said electrodes to pick up a signal of prescribed frequency characteristics, at least one of said electrodes comprising a plurality of splayed electrode fingers; and one or both of said electrodes comprising a group of irregularly spaced electrode fingers and being devoid of electrode fingers which would otherwise make a complete set of equally spaced electrode fingers if combined with said group of irregularly spaced electrode fingers.
Claim 8
Dependent Claim
96 words
A surface elastic wave filter comprising: a piezoelectric body having a surface; a pair of electrodes disposed on said surface for sending and receiving a surface elastic wave between said electrodes to pick up a signal of prescribed frequency characteristics, at least one of said electrodes comprising a plurality of splayed electrode fingers; and one or both of said electrodes comprising a group of irregularly spaced electrode fingers and being devoid of electrode fingers which would otherwise make a complete set of equally spaced electrode fingers if combined with said group of irregularly spaced electrode fingers.
Claim 9
Dependent Claim
76 words
A surface elastic wave filter comprising: a piezoelectric body having a surface; a pair of electrodes disposed on said surface for sending and receiving a surface elastic wave between said electrodes to pick up a signal of prescribed frequency characteristics, at least one of said electrodes comprising a plurality of electrode fingers progressively spread from each other; and a plurality of resistors connected in series respectively with electrode fingers of one or both of said electrodes.
Claim 10
Dependent Claim
76 words
A surface elastic wave filter comprising: a piezoelectric body having a surface; a pair of electrodes disposed on said surface for sending and receiving a surface elastic wave between said electrodes to pick up a signal of prescribed frequency characteristics, at least one of said electrodes comprising a plurality of electrode fingers progressively spread from each other; and a plurality of resistors connected in series respectively with electrode fingers of one or both of said electrodes.
Claim 11
Dependent Claim
33 words
A surface elastic wave filter according to claim 6 or 7, further including a scattering reflector comprising a grating structure and disposed on said surface on which said surface elastic wave is propagated.
Claim 12
Dependent Claim
33 words
A surface elastic wave filter according to claim 6 or 7, further including a scattering reflector comprising a dot structure and disposed on said surface on which said surface elastic wave is propagated.
Claim 13
Dependent Claim
36 words
A surface elastic wave filter according to claim 6 or 7, further including a scattering reflector comprising a grating structure and dot structure and disposed on said surface on which said surface elastic wave is propagated.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-10-30 | 1993-05-01 | 1993-10-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-30 | 1997-05-01 | 1997-10-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-30 | 2001-05-01 | 2001-10-31 | $7700.00 | Window Closed / Lapsed |