Patent US2002622A successfully refreshed from Google Patents.
US3702479A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Space diversity antenna system for uhf satellite communications for helicopters
Assignee: United States Department of the Air Force
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Filing: 1971-07-07
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Granted: 1972-11-07
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Expires: 1991-07-07
Abstract
Abstract Two pair of crossed tube radiators orthogonally fed and spaced approximately one wavelength apart with coaxial choke loading at the end of each radiator provides an antenna system for transmitting and receiving electromagnetic radiation through the plane of the rotating blades of a helicopter on two widely spaced frequencies in the UHF communication band.
Inventors
- 👤 Jerome W Uhrig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:27
CPC Classifications
B; B64; B64C; B64C1/00; B64C1/36; H; H01; H01Q; H01Q1/00; H01Q1/27; H01Q1/28; H01Q1/282; H01Q21/00; H01Q21/24; H01Q21/26; H01Q5/00
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
171 words
An helicopter antenna system for two frequencies of electromagnetic radiation propagating through the plane of the helicopter blades, the said antenna system cooperating with a communication set having a determined impedance, and comprising: 1. a first and a second antenna each having two crossed tubular dipoles of two radiating elements and each tubular dipole having a length of approximately 0.44 wavelength of the higher of the said two frequencies; 2. a choke element inserted in each of the said radiating elements for extending the length of each dipole at the lower frequency to approximately 0.42 wavelength of the lower of the said two frequencies; 3. means for positioning the said two antennas on top of the cabin of the helicopter approximately one wavelength apart at the higher of the two frequencies; 4. means for orthogonally feeding the radiating elements of each of the antennas for circularly polarized electromagnetic radiation; and 5. an impedance matching network coupling the antennas in phaseparallel relationship and providing the said determined impedance of the communication set.
Claim 2
Dependent Claim
171 words
An helicopter antenna system for two frequencies of electromagnetic radiation propagating through the plane of the helicopter blades, the said antenna system cooperating with a communication set having a determined impedance, and comprising: 1. a first and a second antenna each having two crossed tubular dipoles of two radiating elements and each tubular dipole having a length of approximately 0.44 wavelength of the higher of the said two frequencies; 2. a choke element inserted in each of the said radiating elements for extending the length of each dipole at the lower frequency to approximately 0.42 wavelength of the lower of the said two frequencies; 3. means for positioning the said two antennas on top of the cabin of the helicopter approximately one wavelength apart at the higher of the two frequencies; 4. means for orthogonally feeding the radiating elements of each of the antennas for circularly polarized electromagnetic radiation; and 5. an impedance matching network coupling the antennas in phaseparallel relationship and providing the said determined impedance of the communication set.
Claim 3
Dependent Claim
34 words
a choke element inserted in each of the said radiating elements for extending the length of each dipole at the lower frequency to approximately 0.42 wavelength of the lower of the said two frequencies;
Claim 4
Dependent Claim
34 words
a choke element inserted in each of the said radiating elements for extending the length of each dipole at the lower frequency to approximately 0.42 wavelength of the lower of the said two frequencies;
Claim 5
Dependent Claim
93 words
The antenna system as claimed in claim 1 wherein the said choke elements are sections of coaxial cable having the center conductor connected to the shield braid at each end and with a gap in the braid at an electrical length from one end of the cable of approximately one-quarter wavelength at the higher of the two said frequencies, and the said choke elements are inserted in the said tubular radiating elements to position the gap in the braid of each choke element approximately at the end of the respective said tubular radiator.
Claim 6
Dependent Claim
79 words
The antenna system as claimed in claim 2 wherein the said means for orthogonally feeding the radiating elements includes parallel impedance balancing tubes having a length of approximately 0.175 wavelength at the mid-frequency of the said two frequencies each connected at one end to a radiating element at the center of each dipole and grounded at the other end and the said means also includes means for delaying the feed to one dipole of each antenna approximately one-quarter wavelength.
Claim 7
Dependent Claim
26 words
means for positioning the said two antennas on top of the cabin of the helicopter approximately one wavelength apart at the higher of the two frequencies;
Claim 8
Dependent Claim
26 words
means for positioning the said two antennas on top of the cabin of the helicopter approximately one wavelength apart at the higher of the two frequencies;
Claim 9
Dependent Claim
18 words
means for orthogonally feeding the radiating elements of each of the antennas for circularly polarized electromagnetic radiation; and
Claim 10
Dependent Claim
18 words
means for orthogonally feeding the radiating elements of each of the antennas for circularly polarized electromagnetic radiation; and
Claim 11
Dependent Claim
20 words
an impedance matching network coupling the antennas in phase-parallel relationship and providing the said determined impedance of the communication set.
Claim 12
Dependent Claim
20 words
an impedance matching network coupling the antennas in phase-parallel relationship and providing the said determined impedance of the communication set.
References Cited (Backward Citations)
US2422107A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-11-07 | 1976-05-08 | 1976-11-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-07 | 1980-05-08 | 1980-11-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-07 | 1984-05-08 | 1984-11-07 | $7700.00 | Window Closed / Lapsed |