US3579153A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microwave filter
Assignee: AT&T Inc
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Filing: 1967-09-07
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Granted: 1971-05-18
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Expires: 1987-09-07
Abstract
Abstract A microwave bandstop filter of the type in which a plurality of resonant cavities are coupled by irises at intervals to a connecting waveguide. According to the invention the intervals are made three-quarters wavelength and the connecting guide section between each pair of irises is provided with a particularly chosen characteristic impedance which eliminates undesirable responses of the connecting sections without introducing further discontinuities to the structure.
Inventors
- 👤 Han-Chiu Wang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:12
CPC Classifications
H; H01; H01P; H01P1/00; H01P1/20; H01P1/207; H01P1/209
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
98 words
An electromagnetic wave filter having a predetermined transmission characteristic comprising a conductively bounded rectangular waveguide and a plurality of resonant cavities coupled to said guide each by one of a plurality of spaced irises, said guide cross section as defined by said conductive boundary being reduced in at least one dimension in the region of said irises to a dimension which remains uniform from the center of one iris to the center of an adjacent iris in order to include the wave transmission characteristics of said guide between said irises as a contribution to said predetermined transmission characteristic.
Claim 2
Dependent Claim
98 words
An electromagnetic wave filter having a predetermined transmission characteristic comprising a conductively bounded rectangular waveguide and a plurality of resonant cavities coupled to said guide each by one of a plurality of spaced irises, said guide cross section as defined by said conductive boundary being reduced in at least one dimension in the region of said irises to a dimension which remains uniform from the center of one iris to the center of an adjacent iris in order to include the wave transmission characteristics of said guide between said irises as a contribution to said predetermined transmission characteristic.
Claim 3
Dependent Claim
27 words
The filter according to claim 1 wherein said irises are spaced three-quarters of the guide wavelength of said wave energy in the center band of said filter.
Claim 4
Dependent Claim
25 words
The filter according to claim 1 wherein said cavities are approximately one-half the guide wavelength of said wave energy in the band of said filter.
Claim 5
Dependent Claim
81 words
The filter according to claim 1 having the same band edge frequency omega 1 as a given lumped constant prototype filter of the type defined by a plurality of shunt capacitors interconnected by at least one series inductance and in which each component thereof is specified by a normalized g value giving the filter response desired, said filter including three cavities having loaded values of Q1, Q2, and Q3, separated by sections of waveguides of characteristic impedances Z12 and Z23 where
Claim 6
Dependent Claim
34 words
The filter according to claim 1 wherein the narrow dimension of said guide cross section as defined by said conductive boundary is restricted to reduce the characteristic impedance of said guide between said irises.
Claim 7
Dependent Claim
111 words
Electromagnetic wave filter having a predetermined transmission characteristic comprising a conductively bounded waveguide having a given characteristic impedance, a plurality of resonant cavities coupled to said guide each by one of a plurality of spaced irises, the characteristic impedance of said guide being sharply reduced in a step at the transverse cross section of the center of one iris and remaining constant along a length of said guide to the transverse cross section of the center of an adjacent iris, the value of said reduced impedance being proportioned relative to the Q''s of said cavities to make the transmission characteristics of said guide along said length of said predetermined transmission characteristic.
Claim 8
Dependent Claim
111 words
Electromagnetic wave filter having a predetermined transmission characteristic comprising a conductively bounded waveguide having a given characteristic impedance, a plurality of resonant cavities coupled to said guide each by one of a plurality of spaced irises, the characteristic impedance of said guide being sharply reduced in a step at the transverse cross section of the center of one iris and remaining constant along a length of said guide to the transverse cross section of the center of an adjacent iris, the value of said reduced impedance being proportioned relative to the Q''s of said cavities to make the transmission characteristics of said guide along said length of said predetermined transmission characteristic.
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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) | 1974-05-17 | 1974-11-16 | 1975-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-17 | 1978-11-16 | 1979-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-17 | 1982-11-16 | 1983-05-18 | $7700.00 | Window Closed / Lapsed |