Patent US3611213A successfully refreshed from Google Patents.
US3611213A
Expired / Lapsed
US
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Microwave filter
Assignee: International Standard Electric Corp
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Filing: 1969-12-19
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Granted: 1971-10-05
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Expires: 1989-12-19
Abstract
Abstract A microwave filter of the type wherein an H-plane bifurcation provides a first and second channel within a length of rectangular waveguide for the separate propagation of incident energy. In a preferred embodiment, the width of said first channel is reduced and two screws are inserted therein to convert said first channel into a 180* phase shift evanescent filter. Said evanescent filter is coupled to the rectangular waveguide by inserting in said waveguide a screw at each longitudinal end of said bifurcation. The combined outputs of said first and second channel cancel, thereby providing a rejection filter. In a modification of said preferred embodiment, a ferrite is positioned along the sidewalls of said evanescent filter and is subjected to a magnetic field. The strength of said magnetic field controls the phase shift of said evanescent filter and consequently the amount of cancellation achieved, and enables use as a switch.
Inventors
- 👤 George Frederick Craven
- 👤 Richard Finnie Skedd
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 18:56
CPC Classifications
H; H01; H01P; H01P1/00; H01P1/20; H01P1/219
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
93 words
A waveguide filter comprising: a length of waveguide; an H-plane bifurcation having a length equal to a multiple of the guide wavelength for providing in said waveguide a first and second waveguide channel; means for increasing the cutoff frequency of said first waveguide channel above the operating frequency of the waveguide filter; means for terminating predetermined sections of said first channel in a reactance which at the operating frequency is the conjugate of the imaginary characteristic impedance of said first channel; and means for coupling said first channel to said length of waveguide.
Claim 2
Dependent Claim
93 words
A waveguide filter comprising: a length of waveguide; an H-plane bifurcation having a length equal to a multiple of the guide wavelength for providing in said waveguide a first and second waveguide channel; means for increasing the cutoff frequency of said first waveguide channel above the operating frequency of the waveguide filter; means for terminating predetermined sections of said first channel in a reactance which at the operating frequency is the conjugate of the imaginary characteristic impedance of said first channel; and means for coupling said first channel to said length of waveguide.
Claim 3
Dependent Claim
48 words
A waveguide filter, according to claim 1, wherein said means for coupling said first channel to said length of waveguide includes a first and second screw positioned along the longitudinal axis of said waveguide and extending into said first channel, one at each end of said H-plane bifurcation.
Claim 4
Dependent Claim
57 words
A waveguide filter, according to claim 1, wherein said predetermined length includes an even number of predetermined sections and wherein said means for terminating predetermined sections includes an even number of screws, one for each section, positioned along the longitudinal axis of said waveguide and extending into said first channel at the midpoint of said predetermined sections.
Claim 5
Dependent Claim
53 words
A waveguide filter, according to claim 1, wherein said meaNs for increasing the cutoff frequency of said first waveguide channel includes ferrimagnetic material having a length equal to the length of said bifurcation mounted adjacent to the sidewalls of said waveguide channel and means for applying a magnetic field to said ferrimagnetic material.
Claim 6
Dependent Claim
14 words
A waveguide filter, according to claim 1, wherein said ferrimagnetic material is a ferrite.
Claim 7
Dependent Claim
48 words
A waveguide filter, according to claim 4, wherein said means for coupling said first channel to said length of waveguide includes a first and second screw positioned along the longitudinal axis of said waveguide and extending into said first channel, one at each end of said H-plane bifurcation.
Claim 8
Dependent Claim
57 words
A waveguide filter, according to claim 4, wherein said predetermined length includes an even number of predetermined sections and wherein said means for terminating predetermined sections includes an even number of screws, one for each section, positioned along the longitudinal axis of said waveguide and extending into said first channel at the midpoint of said predetermined sections.
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) | 1974-10-04 | 1975-04-05 | 1975-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-04 | 1979-04-05 | 1979-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-04 | 1983-04-05 | 1983-10-05 | $7700.00 | Window Closed / Lapsed |