US4700196A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Highly decoupled cosited antennas
Assignee: United States Department of the Army
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Filing: 1986-08-01
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Granted: 1987-10-13
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Expires: 2006-08-01
Abstract
Abstract Two cosited omnidirectional biconical antennas are respectively tilted plusnd minus 45 degrees (±45°) with respect to the vertical and, therefore, are perpendicular (90°) with respect to each other to effect polarization mismatch and near field decoupling. In combination with the described antennae orientation, high impedance cable chokes are added in series with the coaxial cable antennae feed lines to suppress induced parasitic rf currents.
Inventors
- 👤 Donn V. Campbell
- 👤 Palemon W. Dubowicz
- 👤 Robert T. Hoverter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:59
CPC Classifications
H; H01; H01Q; H01Q25/00; H01Q25/001
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
61 words
A broad band omnidirectional antenna system comprising two cosited dipole antennas, said antennas being tilted plus and minus forty-five degrees with respect to the vertical so that their axes are ninety degrees or perpendicular with respect to each other, and a plurality of high impedance cable chokes added in series with the antennae feed lines to suppress induced parasitic rf currents.
Claim 2
Dependent Claim
61 words
A broad band omnidirectional antenna system comprising two cosited dipole antennas, said antennas being tilted plus and minus forty-five degrees with respect to the vertical so that their axes are ninety degrees or perpendicular with respect to each other, and a plurality of high impedance cable chokes added in series with the antennae feed lines to suppress induced parasitic rf currents.
Claim 3
Dependent Claim
17 words
An antenna system as defined in claim 1 wherein said two cosited dipole antennas are biconical antennas.
Claim 4
Dependent Claim
32 words
An antenna system as defined in claim 2 wherein the spacing (s) between said two cosited biconical antennas is equal to, or less than, one-half wavelength (s≦1/2λ) over the operative frequency range.
Claim 5
Dependent Claim
19 words
An antenna system as defined in claim 3 wherein said operative frequency range is 30 to 90 MHz (VHF).
Claim 6
Dependent Claim
44 words
An antenna system as defined in claim 4 wherein said cable chokes comprise a dual cable choke and a pair of single port chokes each located as close as possible to the point of connecton of an antenna feed line to a respective antenna.
Claim 7
Dependent Claim
130 words
In combination, two cosited omnidirectional biconical antennas, said antennas being respectively tilted plus and minus forty five degrees (±45°) with respect to the vertical so that their axes are ninety degrees (90°) with respect to each other, the spacing (s) between said two cosited biconical antennas being equal to, or less than, one-half wavelength (s≦1/2λ) over the VHF range, a coaxial cable antenna feed line for each of said two antennas, a dual cable choke connected in series with the pair of antenna feed lines, and a single port choke connected in series with each of said antenna feed lines and as close as possible to the point of connection of an antenna feed line to a respective antenna, the series connected chokes serving to suppress induced parasitic rf currents.
Claim 8
Dependent Claim
130 words
In combination, two cosited omnidirectional biconical antennas, said antennas being respectively tilted plus and minus forty five degrees (±45°) with respect to the vertical so that their axes are ninety degrees (90°) with respect to each other, the spacing (s) between said two cosited biconical antennas being equal to, or less than, one-half wavelength (s≦1/2λ) over the VHF range, a coaxial cable antenna feed line for each of said two antennas, a dual cable choke connected in series with the pair of antenna feed lines, and a single port choke connected in series with each of said antenna feed lines and as close as possible to the point of connection of an antenna feed line to a respective antenna, the series connected chokes serving to suppress induced parasitic rf currents.
References Cited (Backward Citations)
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US2229733A
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US2709219A
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US2625655A
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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) | 1990-10-12 | 1991-04-13 | 1991-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-12 | 1995-04-13 | 1995-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-12 | 1999-04-13 | 1999-10-13 | $7700.00 | Window Closed / Lapsed |