US4066986A
Expired / Lapsed
US
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Trapped energy piezoelectric filter
Assignee: Toko Inc
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Filing: 1976-11-29
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Granted: 1978-01-03
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Expires: 1996-11-29
Abstract
Abstract A trapped energy type of piezoelectric filter includes a polarized ceramic wafer 9, input and output electrodes 11, 13 secured to one major surface of the wafer and spaced from each other by a constant width gap, and a ground electrode 15 secured to the opposite major surface underlying the input and output electrodes. The configuration of the ground electrode is made symmetrically concave or convex about its longitudinal axis in varying degrees to thereby control the band pass width, the symmetry of the filter characteristic about a center frequency, and eliminate peak ripples.
Inventors
- 👤 Katsuyoshi Takano
- 👤 Masafumi Matsumoto
- 👤 Kimihiko Orikasa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:07
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/46; H03H9/54; H03H9/56; H03H9/562
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
143 words
In a trapped energy type of electrical band pass filter including a polarized piezoelectric wafer, input and output electrodes secured to one major surface of the wafer, having like planar configurations, and spaced apart from each other at their adjacent edges by a constant width gap, and a planar ground electrode secured to the opposite major surface of the wafer and generally underlying the input and output electrodes, the improvements characterized by: a. The configuration of the ground electrode being symmetrical about a longitudinal center line passing through the centers of the input and output electrodes, and about a transverse center line passing through the gap, and b. The width W 1 of the ground electrode in the area underlying the gap being different from the width W 2 thereof in the area underlying the center portions of the input and output electrodes.
Claim 2
Dependent Claim
143 words
In a trapped energy type of electrical band pass filter including a polarized piezoelectric wafer, input and output electrodes secured to one major surface of the wafer, having like planar configurations, and spaced apart from each other at their adjacent edges by a constant width gap, and a planar ground electrode secured to the opposite major surface of the wafer and generally underlying the input and output electrodes, the improvements characterized by: a. The configuration of the ground electrode being symmetrical about a longitudinal center line passing through the centers of the input and output electrodes, and about a transverse center line passing through the gap, and b. The width W 1 of the ground electrode in the area underlying the gap being different from the width W 2 thereof in the area underlying the center portions of the input and output electrodes.
Claim 3
Dependent Claim
19 words
An electrical band pass filer as defined in claim 1, wherein W 1 is greater than W 2 .
Claim 4
Dependent Claim
19 words
An electrical band pass filter as defined in claim 1, wherein W 2 is greater than W 1 .
Claim 5
Dependent Claim
30 words
An electrical band pass filter as defined in claim 1, wherein the width of the ground electrode changes from W 1 to W 2 in a gradual, smoothly curved manner.
Claim 6
Dependent Claim
30 words
An electrical and pass filter as defined in claim 2, wherein the width of the ground electrode changes from W 1 to W 2 in a gradual, smoothly curved manner.
Claim 7
Dependent Claim
30 words
An electrical band pass filter as defined in claim 3, wherein the width of the ground electrode changes from W 1 to W 2 in a gradual, smoothly curved manner.
References Cited (Backward Citations)
US3638146A
Cited
US4013982A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-01-02 | 1981-07-04 | 1982-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-02 | 1985-07-04 | 1986-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-02 | 1989-07-04 | 1990-01-03 | $7700.00 | Window Closed / Lapsed |