US4998112A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for measuring large antenna arrays
Assignee: United States Department of the Air Force
•
Filing: 1989-08-29
•
Granted: 1991-03-05
•
Expires: 2009-08-29
Abstract
Abstract A method for measuring the far field antenna pattern of a large phased array antenna on a conventional far field range by applying a correction factor to the antenna phase shifters. As the antenna is electronically steered to each of its scan angle, a particular correction factor is applied to each radiating elements to correct the far field antenna pattern to the shortened far field range.
Inventors
- 👤 Peter R. Franchi
- 👤 Harvey Tobin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 08:57
CPC Classifications
G; G01; G01R; G01R29/00; G01R29/08; G01R29/10; H; H01; H01Q; H01Q3/00; H01Q3/26; H01Q3/267
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
146 words
A method for measuring the antenna patterns of large antenna arrays at a distance that is shorter than the calculated far field distances which comprises: (a) applying a signal to each radiating element of a plurality of radiating elements of said large antenna array, (b) adjusting the relative phase difference between adjacent radiating elements in said plurality of radiating element to position the antenna beam at one of a predetermined number of scan angles, (c) applying a correction factor to each radiating element to affect the beam characteristics of the transmitted antenna pattern, (d) measuring said transmitted antenna pattern at a range which is substantially shorter than the calculated far field distance, (e) determining the residual error in said transmitted antenna pattern, and (f) repeating steps a-e to determine the residual error in each transmitted antenna pattern at each angle of said predetermined number of angles.
Claim 2
Independent Claim
146 words
A method for measuring the antenna patterns of large antenna arrays at a distance that is shorter than the calculated far field distances which comprises: (a) applying a signal to each radiating element of a plurality of radiating elements of said large antenna array, (b) adjusting the relative phase difference between adjacent radiating elements in said plurality of radiating element to position the antenna beam at one of a predetermined number of scan angles, (c) applying a correction factor to each radiating element to affect the beam characteristics of the transmitted antenna pattern, (d) measuring said transmitted antenna pattern at a range which is substantially shorter than the calculated far field distance, (e) determining the residual error in said transmitted antenna pattern, and (f) repeating steps a-e to determine the residual error in each transmitted antenna pattern at each angle of said predetermined number of angles.
Claim 3
Dependent Claim
20 words
A method of measuring antenna patterns as described in claim 1 wherein said correction factor comprises a quadratic correction factor.
Claim 4
Dependent Claim
26 words
A method of measuring antenna patterns as described in claim 1 wherein said correction factor comprises a quadratic correction factor and a third order correction factor.
Claim 5
Dependent Claim
27 words
A method of measuring antenna patterns as described in claim 1 wherein step (c) is repeated a calculated number of times to achieve a predetermined error level.
Claim 6
Dependent Claim
29 words
A method of measuring antenna patterns as described in claim 1 wherein said predetermined number of scan angles are spaced every 10 degrees from 90 degrees to 180 degrees.
Claim 7
Dependent Claim
30 words
A method of measuring antenna patterns as described in claim 2 wherein said third order correction factor is repeated a predetermined number of times to achieve a calculated error level.
Claim 8
Dependent Claim
39 words
A method of measuring antenna patterns as described in claim 2 wherein said quadratic correction factor is defined by: ##EQU23## number, R o is the range, D is the diameter of the antenna, and θ is the scan angle.
Claim 9
Dependent Claim
45 words
A method of measuring antenna patterns as described in claim 3 wherein said third order correction factor is defined by: ##EQU24## where K is the wave number, R o is the range, D is the diameter of the antenna, and θ is the scan angle.
References Cited (Backward Citations)
US3302205A
Cited
US3378846A
Cited
US3879733A
Cited
US4201987A
Cited
US4553145A
Cited
US4811023A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-03-04 | 1994-09-03 | 1995-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-03-04 | 1998-09-03 | 1999-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-03-04 | 2002-09-03 | 2003-03-05 | $7700.00 | Window Closed / Lapsed |