Patent US4075583A successfully refreshed from Google Patents.
US4075583A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low loss tuneable filter
Assignee: United States Department of the Navy
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Filing: 1976-05-24
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Granted: 1978-02-21
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Expires: 1996-05-24
Abstract
Abstract A low loss tuneable RF filter including a parallel plate variable capacitornd a helical resonator within an extension of the resonator shield. The capacitor stator is supported on an insulator above one end of the helix while the rotor is mounted between the walls of the resonator shield. The rotor plates are wider than the stator plates by about 20%.
Inventors
- 👤 Joseph E. Kershaw
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:05
CPC Classifications
H; H03; H03H; H03H5/00; H03H5/02; H03H1/00
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
190 words
A low loss tuneable RF filter capable of being continuously tuned over a frequency range of at least 2:1 comprising: a. an enclosed housing forming a shield, b. a helical coil resonator positioned in one end of said housing, c. a variable capacitor having a rotor and a stator positioned in the other end of said housing, d. one end of said helical coil being electrically connected to said housing at a point intermediate the end of said housing in which said variable capacitor is positioned and the end of said housing in which said helical is positioned, the other end of said helical coil being electrically connected to the stator of said variable capacitor, e. the rotor of said varible capacitor being mounted on a shaft supported by opposing walls of said housing and being electrically connected to said housing to provide optimum Q for said helical coil resonator, and f. said rotor and stator being dimensioned to provide said rotor with a uniform width that is wider than said stator and establishing a constant overlap as the rotor is rotated for tuning said filter over said frequency range.
Claim 2
Dependent Claim
190 words
A low loss tuneable RF filter capable of being continuously tuned over a frequency range of at least 2:1 comprising: a. an enclosed housing forming a shield, b. a helical coil resonator positioned in one end of said housing, c. a variable capacitor having a rotor and a stator positioned in the other end of said housing, d. one end of said helical coil being electrically connected to said housing at a point intermediate the end of said housing in which said variable capacitor is positioned and the end of said housing in which said helical is positioned, the other end of said helical coil being electrically connected to the stator of said variable capacitor, e. the rotor of said varible capacitor being mounted on a shaft supported by opposing walls of said housing and being electrically connected to said housing to provide optimum Q for said helical coil resonator, and f. said rotor and stator being dimensioned to provide said rotor with a uniform width that is wider than said stator and establishing a constant overlap as the rotor is rotated for tuning said filter over said frequency range.
Claim 3
Dependent Claim
40 words
The tuneable filter of claim 1 wherein the capacitor stator is supported on an insulator forming a partition between the portion of the housing wherein said coil is mounted and the portion of the housing wherein said capacitor is mounted.
Claim 4
Dependent Claim
36 words
The tuneable filter of claim 2 wherein the rotor plates are constantly approximately 20% wider than the stator plates of said capacitor as the rotor plates are moved from a meshed position to the unmeshed position.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-02-20 | 1981-08-22 | 1982-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-20 | 1985-08-22 | 1986-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-20 | 1989-08-22 | 1990-02-21 | $7700.00 | Window Closed / Lapsed |