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US3587009A
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Electromagnetic filters wherein waveguide walls comprise alternate conductivity sections
Assignee: AT&T Inc
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Filing: 1968-12-27
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Granted: 1971-06-22
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Expires: 1988-12-27
Abstract
Abstract A high pass filter comprising a section of waveguide having alternate sections of different wall conductivity to produce a sharper cutoff and more linear phase propagation near cutoff. Low-pass, band-pass and band-reject filters are also described.
Inventors
- 👤 Lynden U Kibler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:57
CPC Classifications
H; H01; H01P; H01P3/00; H01P3/12; H01P3/127; H01P1/00; H01P1/20; H01P1/207
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
36 words
An electromagnetic wave filter comprising a waveguide of essentially uniform diameter having conductively bounded walls, said walls comprising alternate sections of conductive material having different conductivities, the ratio of the conductivities being between two and fifteen.
Claim 2
Dependent Claim
36 words
An electromagnetic wave filter comprising a waveguide of essentially uniform diameter having conductively bounded walls, said walls comprising alternate sections of conductive material having different conductivities, the ratio of the conductivities being between two and fifteen.
Claim 3
Dependent Claim
17 words
A device according to claim 1 wherein there are between 10 and 50 sections of each conductivity.
Claim 4
Dependent Claim
32 words
A device according to claim 2 wherein said waveguide has a cutoff frequency and the length of two of said alternate sections lies between 0.25 and 5 wavelengths at the cutoff frequency.
Claim 5
Dependent Claim
27 words
A device according to claim 3 wherein the length of a section of the lower conductivity is greater than that of a section of the higher conductivity.
Claim 6
Dependent Claim
26 words
An electromagnetic filter comprising a filter in accordance with claim 1 and means for selectively extracting the transmitted and the reflected portions of an input signal.
Claim 7
Dependent Claim
26 words
An electromagnetic wave low-pass filter comprising a three-port circulator including an input, a filter according to claim 1 terminating the second port and an output port.
Claim 8
Dependent Claim
16 words
A band-pass filter including a pair of filters according to claim 1 having different frequency characteristics.
Claim 9
Dependent Claim
16 words
A band-reject filter including a pair of filters according to claim 1 having different frequency characteristics.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-21 | 1974-12-21 | 1975-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-21 | 1978-12-21 | 1979-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-21 | 1982-12-21 | 1983-06-22 | $7700.00 | Window Closed / Lapsed |