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EP0401995A2
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Microwave diplexer
Assignee: Raytheon Co
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Filing: 1990-05-18
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Granted: —
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Expires: 2010-05-18
Abstract
Abstract A diplexer (10) for electromagnetic signals of higher and lower frequency is formed of a common waveguide channel (20) for both signals, the common channel branching into a through waveguide channel (26) and a side waveguide channel (28). The through channel includes a filter (42) having a pass band for propagation of the lower frequency signal and inhibiting propagation of the higher frequency signal. The side channel is formed as a waveguide below cut-off frequency with respect to the lower frequency signal for inhibiting propagation of the lower frequency signal while permitting propagation of the higher frequency signal. A coupling aperture formed as a slot (58) resonant at the higher frequency is located in a waveguide wall at an integral number of quarter guide wavelengths in front of the filter for coupling the higher frequency signal between the common and the side channels.
Inventors
- 👤 Mon N. Wong
- 👤 Thomas F. Foster
- 👤 Gregory D. Kroupa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 11:27
CPC Classifications
H; H01; H01P; H01P1/00; H01P1/20; H01P1/213; H01P1/2138
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
192 words
A microwave diplexer comprising: a first section of waveguide and a second section of waveguide joining said first section, said first section serving as a common channel of said diplexer and terminating in a common port for propagation of radiation at two frequencies of which one frequency is higher than the other frequency, said second section serving as a through channel of said diplexer and terminating in a through port for propagation of radiation at a lower frequency of said two frequencies; a third section of waveguide joining said first section of waveguide, said third section serving as a side channel of said diplexer and terminating in a side port for propagation of radiation at a higher frequency of said two frequencies; filter means in said through channel for inhibiting a propagation of radiation at said higher frequency while permitting propagation of the lower frequency radiation; and wherein at least a portion of said side channel has cross-sectional dimensions large enough to sustain a propagating mode of the higher frequency radiation and small enough to provide an evanescent mode for the lower frequency radiation to inhibit propagation of the lower frequency radiation.
Claim 2
Dependent Claim
192 words
A microwave diplexer comprising: a first section of waveguide and a second section of waveguide joining said first section, said first section serving as a common channel of said diplexer and terminating in a common port for propagation of radiation at two frequencies of which one frequency is higher than the other frequency, said second section serving as a through channel of said diplexer and terminating in a through port for propagation of radiation at a lower frequency of said two frequencies; a third section of waveguide joining said first section of waveguide, said third section serving as a side channel of said diplexer and terminating in a side port for propagation of radiation at a higher frequency of said two frequencies; filter means in said through channel for inhibiting a propagation of radiation at said higher frequency while permitting propagation of the lower frequency radiation; and wherein at least a portion of said side channel has cross-sectional dimensions large enough to sustain a propagating mode of the higher frequency radiation and small enough to provide an evanescent mode for the lower frequency radiation to inhibit propagation of the lower frequency radiation.
Claim 3
Dependent Claim
94 words
A diplexer according to Claim 1 wherein each of said sections of waveguide has a rectangular cross-section and comprises two opposed broad walls joined by two opposed sidewalls which are narrower than said broad walls, said side channel joining said common channel at a first broad wall of said first waveguide section for supporting a transverse electric mode of radiation in each of said waveguide sections with electric field parallel to a sidewall, there being a coupling aperture in said first broad wall for coupling radiation from said common channel to said side channel.
Claim 4
Dependent Claim
57 words
A diplexer according to Claim 2 wherein the aperture in said first broad wall is formed as an elongated resonant slot having a perimeter approximately equal to one free-space wavelength of the higher frequency radiation, a longitudinal axis of the slot extending in a direction perpendicular to the sidewalls of said first and said second waveguide sections.
Claim 5
Dependent Claim
113 words
A diplexer according to Claim 3 wherein said filter means comprises a plurality of inductive irises spaced apart along said second waveguide section to define at least one cavity resonant with the irises at the lower frequency to provide a pass band for propagation of the lower frequency radiation, a first of said irises closest said coupling aperture being located an odd number of one-quarter guide wavelengths at the higher-frequency radiation from said coupling aperture to reflect the higher frequency radiation back to the coupling aperture with a maximum value of electric field at the coupling aperture to maximize propagation of the higher frequency radiation between said common channel and said side channel.
Claim 6
Dependent Claim
59 words
A diplexer according to Claim 4 wherein said filter means comprises a plurality of said cavities, one of said irises which is centrally located among said cavities having a slot of narrower width than a slot of said first iris, there being capacitive tuning screws in a broad wall of said second waveguide section for tuning said filter means.
Claim 7
Dependent Claim
42 words
A diplexer according to Claim 4 wherein said portion of said side channel is reduced in cross-section by reduction of the width of the broad walls of said third waveguide section at said portion to inhibit propagation of the lower frequency radiation.
Claim 8
Dependent Claim
39 words
A diplexer according to Claim 4 further comprising shims disposed in said portion of said side channel alongside sidewalls thereof to reduce the cross-section of said portion of said side channel to inhibit propagation of the lower frequency radiation.
References Cited (Backward Citations)
No citation records indexed.
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