US3696436A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cassegrain antenna with absorber to reduce back radiation
Assignee: KDDI Corp
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Filing: 1970-09-15
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Granted: 1972-10-03
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Expires: 1990-09-15
Abstract
Abstract An antenna using a primary horn radiator and at least one reflector, in which a wave absorber is positioned at a limited area of the center portion of the reflector, for absorbing electric waves which would otherwise reflect from that limited area and be reapplied to the horn radiator, so that reaction between the feed radiator and the reflector is substantially eliminated.
Inventors
- 👤 Hiroshi Yokoi
- 👤 Hiroshi Fukumuro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 18:55
CPC Classifications
H; H01; H01Q; H01Q17/00; H01Q17/001; H01Q19/00; H01Q19/02; H01Q19/021; H01Q19/025
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
129 words
A Cassegrain antenna system comprising a main reflector for electric energy waves, a sub-reflector for directing electric energy waves toward said main reflector, a primary horn radiator for directing electric energy waves toward said sub-reflector, and wave-absorging means consisting of an article of electric energy wave-absorbing material disposed only on a limited area of a central portion of said sub-reflector for absorbing only a portion of said electric energy waves directed toward said subreflector, which said portion of said waves consists of only those said waves which would otherwise reflect back to said primary horn radiator; said limited area being substantially equal to a projection of the geometrical shadow area of the subreflector on the sub-reflector caused by a light from a point at infinity to said main reflector.
Claim 2
Dependent Claim
129 words
A Cassegrain antenna system comprising a main reflector for electric energy waves, a sub-reflector for directing electric energy waves toward said main reflector, a primary horn radiator for directing electric energy waves toward said sub-reflector, and wave-absorging means consisting of an article of electric energy wave-absorbing material disposed only on a limited area of a central portion of said sub-reflector for absorbing only a portion of said electric energy waves directed toward said subreflector, which said portion of said waves consists of only those said waves which would otherwise reflect back to said primary horn radiator; said limited area being substantially equal to a projection of the geometrical shadow area of the subreflector on the sub-reflector caused by a light from a point at infinity to said main reflector.
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) | 1975-10-03 | 1976-04-03 | 1976-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-03 | 1980-04-03 | 1980-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-03 | 1984-04-03 | 1984-10-03 | $7700.00 | Window Closed / Lapsed |