US3681771A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Retroflector dipole antenna array and method of making
Assignee: MACDOWELL ASSOCIATES Inc
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Filing: 1970-03-23
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Granted: 1972-08-01
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Expires: 1990-03-23
Abstract
Abstract A method of making an antenna array and an antenna array apparatus of a low-cost wide angle retroreflector is provided in which a printed circuit board has a plurality of antenna elements etched on one side thereof and a ground plane on the other separated by dielectric material of a predetermined thickness. Baluns are attached through the printed circuit board to each antenna element and to the ground plane and transmission lines of equal length connect spaced pairs of antenna elements utilizing the balun and matching the transmission line to the antenna element.
Inventors
- 👤 Bernard L Lewis
- 👤 James E Macdowell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:29
CPC Classifications
H; H01; H01Q; H01Q15/00; H01Q15/14; H01P; H01P5/00; H01P5/08; H01P5/10; H01Q21/00; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49016
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
142 words
A method of making a retroreflector apparatus comprising the steps of: a. etching a printed circuit board with a plurality of antenna elements at predetermined locations on one side; said printed circuit board having a ground plane on a second side thereof; b. attaching a balun to each said antenna element on one side of said printed circuit board; c. attaching each said balun to said ground plane on said second side of said printed circuit board; d. cutting a plurality of transmission lines to the approximate same electrical length for connection between spaced baluns; e. attaching each of said plurality of transmission lines between spaced pairs of baluns one end of each said transmission line being attached to only one balun and said baluns being located in predetermined spaced relationship to each other whereby a wide angle retroreflector apparatus is produced.
Claim 2
Independent Claim
142 words
A method of making a retroreflector apparatus comprising the steps of: a. etching a printed circuit board with a plurality of antenna elements at predetermined locations on one side; said printed circuit board having a ground plane on a second side thereof; b. attaching a balun to each said antenna element on one side of said printed circuit board; c. attaching each said balun to said ground plane on said second side of said printed circuit board; d. cutting a plurality of transmission lines to the approximate same electrical length for connection between spaced baluns; e. attaching each of said plurality of transmission lines between spaced pairs of baluns one end of each said transmission line being attached to only one balun and said baluns being located in predetermined spaced relationship to each other whereby a wide angle retroreflector apparatus is produced.
Claim 3
Dependent Claim
41 words
The method in accordance with claim 1 but including the step of drilling holes in said printed circuit board at predetermined locations for inserting said balun in prior to attaching each said balun to each side of said printed circuit board.
Claim 4
Dependent Claim
54 words
The method in accordance with claim 2 but including the step of attaching said baluns to said printed circuit board by positioning each balun in a hole in said printed circuit board and flow soldering said balun to a ground plane of said printed circuit board on the opposite side from said antenna elements.
Claim 5
Dependent Claim
30 words
The method in accordance with claim 3 in which said baluns are attached to each antenna element by flow soldering said baluns following attaching said baluns to said ground plane.
Claim 6
Dependent Claim
22 words
The method in accordance with claim 4 which includes attaching the center conductor of said transmission line to one said antenna element.
Claim 7
Dependent Claim
26 words
The method in accordance with claim 5 but including the step of machining baluns from tubing prior to attaching a balun to each said antenna element.
Claim 8
Dependent Claim
133 words
A retroreflector apparatus comprising in combination: a. a printed circuit board having antenna elements etched on one side thereof and a ground plane on the other side thereof; b. said printed circuit board having tubular shaped baluns with parallel slots in the walls of one end thereof, said slots being of a length corresponding to approximately one quarter of the frequency of said retroreflector and each said balun being attached to said ground plane and to one said antenna element; and c. a plurality of transmission lines of approximately equal lengths; each said transmission line being connected between a pair of spaced baluns and each end of each said transmission line being attached to only one spaced balun whereby a wide angle retroreflector array is provided with pairs of spaced interconnected antenna elements.
Claim 9
Dependent Claim
133 words
A retroreflector apparatus comprising in combination: a. a printed circuit board having antenna elements etched on one side thereof and a ground plane on the other side thereof; b. said printed circuit board having tubular shaped baluns with parallel slots in the walls of one end thereof, said slots being of a length corresponding to approximately one quarter of the frequency of said retroreflector and each said balun being attached to said ground plane and to one said antenna element; and c. a plurality of transmission lines of approximately equal lengths; each said transmission line being connected between a pair of spaced baluns and each end of each said transmission line being attached to only one spaced balun whereby a wide angle retroreflector array is provided with pairs of spaced interconnected antenna elements.
Claim 10
Dependent Claim
43 words
The apparatus according to claim 7 in which each said transmission line is a coaxial cable having each end thereof of said transmission line braid attached to one said balun and each end of each center conductor attached to one said antenna element.
Claim 11
Dependent Claim
13 words
The apparatus according to claim 8 in which said antenna elements are dipoles.
Claim 12
Dependent Claim
23 words
The apparatus according to claim 9 in which said printed circuit board has a copper clad ground plane and copper clad antenna elements.
Claim 13
Dependent Claim
30 words
The apparatus according to claim 10 in which said dipoles are aligned in intermittent rows with said elements in each row running perpendicular to the elements in each preceding row.
References Cited (Backward Citations)
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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) | 1975-08-01 | 1976-01-31 | 1976-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-01 | 1980-01-31 | 1980-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-01 | 1984-01-31 | 1984-08-01 | $7700.00 | Window Closed / Lapsed |