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US4630009A
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US
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Cascade waveguide triple-mode filters useable as a group delay equalizer
Assignee: Honeywell Ltd Canada
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Filing: 1984-01-24
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Granted: 1986-12-16
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Expires: 2004-01-24
Abstract
Abstract A bandpass filter has a plurality of cascade wave-guide cavities each resonating in three independent orthogonal modes. The cavities can be cylindrical or have a square cross-section. Where the cavities are circular, each cavity resonates in TE 111 or TE 010 modes simultaneously. Where the cavities have a square cross-section, each cavity resonates in TE 011 and TM 110 modes simultaneously. Between each triple-mode cavity, there is located an iris having an aperture with four separate radial slots that are offset from a center of the iris. The filter is capable of producing an elliptic function response. In a variation of the invention, an allpass filter has an output that is short circuited and, when used in conjunction with a circulator, it functions as a group delay equalizer. Previous triple-mode filters are not capable of producing an acceptable result relative to dual-mode filters.
Inventors
- 👤 Wai-Cheung Tang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 22:40
CPC Classifications
H; H01; H01P; H01P1/00; H01P1/20; H01P1/207; H01P1/208; H01P1/2082
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
124 words
A bandpass filter comprising a plurality of cascade waveguide cavities, each cavity having two ends that are parallel to one another, said filter having an input and an output, with at least two adjacent cavities mounted end to end relative to one another and resonating at their resonant frequency in three independent orthogonal modes, at least one of said modes being non-identical to the other two modes, with an inter-cavity coupling iris located between adjacent three mode cavities that are mounted end to end relative to one another, each iris containing an aperture that is able to independently control three inter-cavity couplings simultaneously, when said filter is operated in a suitable propagation mode for input and output coupling, to produce an elliptic function response.
Claim 2
Dependent Claim
124 words
A bandpass filter comprising a plurality of cascade waveguide cavities, each cavity having two ends that are parallel to one another, said filter having an input and an output, with at least two adjacent cavities mounted end to end relative to one another and resonating at their resonant frequency in three independent orthogonal modes, at least one of said modes being non-identical to the other two modes, with an inter-cavity coupling iris located between adjacent three mode cavities that are mounted end to end relative to one another, each iris containing an aperture that is able to independently control three inter-cavity couplings simultaneously, when said filter is operated in a suitable propagation mode for input and output coupling, to produce an elliptic function response.
Claim 3
Dependent Claim
46 words
A bandpass filter as claimed in claim 1 wherein each aperture is comprised of four non-contacting radial slots, said slots being 90° apart from one another so that there are two sets of two slots each, the slots of each set being aligned with one another.
Claim 4
Dependent Claim
22 words
A bandpass filter as claimed in claim 2 wherein all of the radial slots are offset from a centre of the iris.
Claim 5
Dependent Claim
58 words
A bandpass filter as claimed in claim 3 wherein the slots of each set are the same length and offset from said centre by an equal distance, the slots of one set having a different length and being offset from the centre by a different distance than the length and distance of the slots of the other set.
Claim 6
Dependent Claim
27 words
A bandpass filter as claimed in claim 3 wherein the filter has two cavities only, both resonating at their resonant frequency in said three independent orthogonal modes.
Claim 7
Dependent Claim
40 words
A bandpass filter as claimed in any one of claims 1, 4 or 5 wherein the cavities are cylindrical and the filter is operated in a TE 11n propagation mode for input and output coupling, n being a positive integer.
Claim 8
Dependent Claim
35 words
A bandpass filter as claimed in any one of claims 1, 4 or 5 wherein the cavities are cylindrical and the filter is operated in a TE 111 propagation mode for input and output coupling.
Claim 9
Dependent Claim
42 words
A bandpass filter as claimed in any one of claims 1, 4 or 5 wherein the cavities have a square cross-section and the filter is operated in a TE 10n propagation mode for input and output coupling, n being a positive integer.
Claim 10
Dependent Claim
37 words
A bandpass filter as claimed in any one of claims 1, 4 or 5 wherein the cavities have a square cross-section and the filter is operated in a TE 101 propagation mode for input and output coupling.
Claim 11
Dependent Claim
30 words
A bandpass filter as claimed in any one of claims 1, 4 or 5 wherein at least one cavity is cylindrical and at least one cavity has a square cross-section.
Claim 12
Dependent Claim
41 words
A bandpass filter as claimed in any one of claims 1, 4 or 5 when the filter is of the order N, N being an integer multiple of three and the number of cavities is equal to N divided by three.
Claim 13
Dependent Claim
30 words
A bandpass filter as claimed in any one of claims 1, 2 or 5 wherein there is at least one cavity that does not resonate in three independent orthogonal modes.
Claim 14
Dependent Claim
141 words
An allpass filter comprising at least two adjacent cascade waveguide cavities, each cavity having two ends that are parallel to one another, said filter having an input and an output, two cavities being mounted end to end relative to one another and resonating at their resonant frequency in three independent orthogonal modes, at least one of said modes being non-identical to the other two modes with an inter-cavity coupling iris located between adjacent three mode cavities that are mounted end to end relative to one another, each iris containing an aperture that is able to independently control three inter-cavity couplings simultaneously, when said filter is operated in a suitable propagation mode for input and output coupling, an output of said filter being short circuited so that the filter will function as a group delay equalizer, when used with a non-reciprocal structure.
Claim 15
Dependent Claim
141 words
An allpass filter comprising at least two adjacent cascade waveguide cavities, each cavity having two ends that are parallel to one another, said filter having an input and an output, two cavities being mounted end to end relative to one another and resonating at their resonant frequency in three independent orthogonal modes, at least one of said modes being non-identical to the other two modes with an inter-cavity coupling iris located between adjacent three mode cavities that are mounted end to end relative to one another, each iris containing an aperture that is able to independently control three inter-cavity couplings simultaneously, when said filter is operated in a suitable propagation mode for input and output coupling, an output of said filter being short circuited so that the filter will function as a group delay equalizer, when used with a non-reciprocal structure.
Claim 16
Dependent Claim
40 words
A filter as claimed in claim 13 wherein each aperture has four radial slots located 90° apart from one another, so that there are two sets of two slots each, the slots of each set being aligned with one another.
Claim 17
Dependent Claim
28 words
A filter as claimed in claim 14 wherein all of the radial slots are offset from a centre of the iris and the non-reciprocal structure is a circulator.
Claim 18
Dependent Claim
13 words
A filter as claimed in claim 15 wherein the filter has two cavities.
Claim 19
Dependent Claim
57 words
A filter as claimed in claim 16 wherein the slots of each set are the same length and offset from said centre by an equal distance, the slots of one set having a different length and being offset from the centre by a different distance than the length and distance of the slots of the other set.
Claim 20
Dependent Claim
40 words
A bandpass filter as claimed in any one of claims 13, 15 or 17 wherein the cavities are cylindrical and the filter is operated in a TE 11n propagation mode for input and output coupling, n being a positive integer.
Claim 21
Dependent Claim
34 words
A filter as claimed in any one of claims 13, 15 or 17 wherein the cavities are cylindrical and the filter is operated in a TE 111 propagation mode for input and output coupling.
Claim 22
Dependent Claim
41 words
A filter as claimed in any one of claims 13, 15 or 17 wherein the cavities have a square cross-section and the filter is operated in a TE 10n propagation mode for input and output coupling, n being a positive integer.
Claim 23
Dependent Claim
36 words
A filter as claimed in any one of claims 13, 15 or 17 wherein the cavities have a square cross-section and the filter is operated in a TE 101 propagation mode for input and output coupling.
Claim 24
Dependent Claim
29 words
A filter as claimed in any one of claims 13, 15 or 17 wherein at least one cavity is cylindrical and at least one cavity has a square cross-section.
Claim 25
Dependent Claim
23 words
A bandpass filter as claimed in any one of claims 1, 4 or 5 wherein there is a dielectric resonator in each cavity.
Claim 26
Dependent Claim
22 words
A filter as claimed in any one of claims 13, 15 or 16 wherein there is a dielectric resonator in each cavity.
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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) | 1989-12-15 | 1990-06-16 | 1990-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-15 | 1994-06-16 | 1994-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-15 | 1998-06-16 | 1998-12-16 | $7700.00 | Window Closed / Lapsed |