US4785266A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dielectric rod polarizer having wedge shape polarizing portions
Assignee: BAE Systems Electronics Ltd
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Filing: 1987-07-06
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Granted: 1988-11-15
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Expires: 2007-07-06
Abstract
Abstract A microwave polarizer is provided in the form of a wedge at the termination of a rod of dielectric material. Preferably the wedge tapers exponentially in order to provide a good impedance match. Circularly polarized radiation propagating along the rod experiences a differential phase shift at the wedge. This phase shift may be arranged to be 90°, so that linearly polarized radiation exits from the wedge. A continuous circular or square guide is used to contain the dielectric rod so that simultaneous orthogonal signals can be converted to or from circular polarizations. Such a wedge termination may be provided at the end of a splashplate or polyrod antenna feed, for a satellite communication system, where right-handed circular polarization is used on the up-link and left-handed circular polarization is used on the down link. The conventional orthomode transducer may be dispensed with, thereby enabling the sub-reflector to be located closer to the main reflector, thus reducing blockage and increasing the bandwidth.
Inventors
- 👤 Paul Newham
- 👤 Bernard J. Andrews
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 06:28
CPC Classifications
H; H01; H01Q; H01Q13/00; H01Q13/20; H01Q13/24; H01P; H01P1/00; H01P1/165; H01P1/17; H01P1/172; H01Q13/02; H01Q13/0241; H01Q19/00; H01Q19/06; H01Q19/08
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
201 words
A radio frequency polarizer, comprising: (a) a rod of dielectric material elongated along a length direction, (b) said rod having a body portion and at least one end portion, said body portion having a cross-section transverse to said length direction and said cross-section having a width direction transverse to said length direction, (c) said end portion having a length along said length direction and a wedge formation comprising a reduction of rod dimension in said width direction only, (d) a tubular waveguide elongated along a length direction and containing said rod therein, said length direction of said rod coinciding with said length direction of said tubular waveguide, (e) said tubular waveguide having a cross-section for carrying orthogonal plane-polarized waves, and said cross-section of said body portion conforming to and being a close fit in said cross-section of said tubular waveguide, (f) said cross-section of said tubular waveguide being constant throughout said length of said wedge formation, said wedge formation being non-critically positioned longitudinally along and within said tubular waveguide, and (g) said wedge formation of said rod of dielectric material effecting a differential phase-shift between orthogonal components of each of said orthogonal plane-polarized waves for conversion between plane and non-plane polarization.
Claim 2
Dependent Claim
201 words
A radio frequency polarizer, comprising: (a) a rod of dielectric material elongated along a length direction, (b) said rod having a body portion and at least one end portion, said body portion having a cross-section transverse to said length direction and said cross-section having a width direction transverse to said length direction, (c) said end portion having a length along said length direction and a wedge formation comprising a reduction of rod dimension in said width direction only, (d) a tubular waveguide elongated along a length direction and containing said rod therein, said length direction of said rod coinciding with said length direction of said tubular waveguide, (e) said tubular waveguide having a cross-section for carrying orthogonal plane-polarized waves, and said cross-section of said body portion conforming to and being a close fit in said cross-section of said tubular waveguide, (f) said cross-section of said tubular waveguide being constant throughout said length of said wedge formation, said wedge formation being non-critically positioned longitudinally along and within said tubular waveguide, and (g) said wedge formation of said rod of dielectric material effecting a differential phase-shift between orthogonal components of each of said orthogonal plane-polarized waves for conversion between plane and non-plane polarization.
Claim 3
Dependent Claim
48 words
A polarizer according to claim 1, wherein said wedge formation comprises two surfaces converging toward a common plane parallel to said length direction of said rod, said two surfaces being of concave curvature in a longitudinal plane perpendicular to said common plane for providing an improved impedance match.
Claim 4
Dependent Claim
67 words
A polarizer according to claim 2, wherein said rod comprises a body portion terminated by said wedge formation, said wedge formation comprising a thin edge in said common plane, said surfaces diverging from said thin edge toward said body portion, and wherein said curvature is of exponential form, the thickness of said wedge formation increasing exponentially from said thin edge to said body portion of said rod.
Claim 5
Dependent Claim
50 words
A polarizer according to claim 3, wherein said length of wedge formation in conjunction with a value of dielectric constant of said dielectric material produce said differential phase-shift of 90° between a plane-polarized wave component propagating in said common plane and a plane-polarized wave component propagating in said longitudinal plane.
Claim 6
Dependent Claim
35 words
A polarizer according to claim 1, wherein each opposite end of said rod terminates in said wedge formation, each wedge formation contributing part of said differential phase-shift between said components of each orthogonal plane-polarized wave.
Claim 7
Dependent Claim
14 words
A polarizer according to claim 1, wherein said tubular waveguide is of circular cross-section.
Claim 8
Dependent Claim
35 words
A polarizer according to claim 1, wherein said plane-polarized waves have operative frequencies, and wherein said length of said wedge formation is between one and two wavelengths at the operative frequencies of said plane-polarized waves.
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) | 1991-11-15 | 1992-05-16 | 1992-11-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-15 | 1996-05-16 | 1996-11-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-15 | 2000-05-16 | 2000-11-15 | $7700.00 | Window Closed / Lapsed |