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US4489313A
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US
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Signal direction determining system and directional loop antenna array therefor
Assignee: Sensormatic Electronics Corp
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Filing: 1982-09-01
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Granted: 1984-12-18
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Expires: 2002-09-01
Abstract
Abstract A directional loop antenna array is provided by two flat parallel spaced apart open loops with a shorted turn disposed between the open loops equidistant therefrom. The signals from the open loops are vectorially added and subtracted in a sum and difference circuit and the phase angle between the sum and difference signals is ascertained in a phase detector circuit that feeds an indicator. The so determined phase angle is either greater or less than 90° depending upon the relative magnitudes of the loop signals.
Inventors
- 👤 Henry F. Pfister
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:28
CPC Classifications
G; G08; G08B; G08B21/00; G08B21/18; G08B21/185; G01; G01S; G01S3/00; G01S3/02; G01S3/14; G01S3/28; G01S3/32; G08B13/00; G08B13/22; G08B13/24; G08B13/2402; G08B13/2451; G08B13/2462; G08B13/2465; G08B13/2468; G08B13/2474; G08B13/2477
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
120 words
A signal direction determining system for providing an output indicative of the direction to a source of AC signals from a directional loop antenna array where said array includes at least a pair of open loops of electrically conductive material, said system comprising means coupled to said open loops for providing a first output corresponding to the sum of any AC signals induced in said loops by said source and a second output corresponding to the difference between said induced signals; and phase detecting and indicating means coupled to said first and second outputs for providing a further output dependent upon which open loop has the greater induced signal, said further output being indicative of the direction to said source.
Claim 2
Dependent Claim
120 words
A signal direction determining system for providing an output indicative of the direction to a source of AC signals from a directional loop antenna array where said array includes at least a pair of open loops of electrically conductive material, said system comprising means coupled to said open loops for providing a first output corresponding to the sum of any AC signals induced in said loops by said source and a second output corresponding to the difference between said induced signals; and phase detecting and indicating means coupled to said first and second outputs for providing a further output dependent upon which open loop has the greater induced signal, said further output being indicative of the direction to said source.
Claim 3
Dependent Claim
27 words
A signal direction determining system according to claim 1, wherein at least one closed loop of electrically conductive material is located between said pair of open loops.
Claim 4
Dependent Claim
29 words
A signal direction determining system according to claim 2, wherein said open loops are substantially congruent, each of flat construction, and in parallel coaxial relationship one to the other.
Claim 5
Dependent Claim
31 words
A signal direction determining system according to claim 3, wherein said closed loop consists of a metal door frame, and said open loops are disposed on opposite sides of said frame.
Claim 6
Dependent Claim
20 words
A signal direction determining system according to claim 3, wherein said closed loop consists of at least one shorted turn.
Claim 7
Dependent Claim
40 words
A directional loop antenna array comprising at least one closed loop of electrically conductive material located between a pair of open loops of electrically conductive material, said open loops each having means for effecting coupling thereto of a utilization device.
Claim 8
Dependent Claim
40 words
A directional loop antenna array comprising at least one closed loop of electrically conductive material located between a pair of open loops of electrically conductive material, said open loops each having means for effecting coupling thereto of a utilization device.
Claim 9
Dependent Claim
29 words
A directional loop antenna array according to claim 6, wherein said open loops are substantially congruent, each of flat construction, and in parallel coaxial relationship one to the other.
Claim 10
Dependent Claim
31 words
A directional loop antenna array according to claim 7, wherein said closed loop consists of a metal door frame, and said open loops are disposed in opposite sides of said frame.
Claim 11
Dependent Claim
20 words
A directional loop antenna array according to claim 7, wherein said closed loop consists of at least one shorted turn.
Claim 12
Dependent Claim
24 words
A directional loop antenna array according to claim 9, wherein said closed loop is spaced between parallel to and equidistant from said open loops.
References Cited (Backward Citations)
US2657313A
Cited
US4375289A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-12-18 | 1988-06-18 | 1988-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-12-18 | 1992-06-18 | 1992-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-12-18 | 1996-06-18 | 1996-12-18 | $7700.00 | Window Closed / Lapsed |