US4424483A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microwave radiation monitor
Assignee: Lockheed Martin Corp
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Filing: 1981-04-16
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Granted: 1984-01-03
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Expires: 2001-04-16
Abstract
Abstract This portable microwave radiation monitor utilizes an antenna formed in a dual Archimedean spiral. The ellipse ratio of the spiral is minimized by selective placement of resistive means over a portion of the antenna and the power density of the electric field is indicated on a meter connected via diode means to the inner terminals of the antenna.
Inventors
- 👤 Edward E. Aslan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:41
CPC Classifications
G; G01; G01R; G01R21/00; G01R21/10; G01R29/00; G01R29/08; G01R29/0864; G01R29/0878
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
121 words
A microwave radiation monitor comprising: a dual Archimedean spiral antenna defined by r=aθ, wherein r is the radius from the center to a point on the curve of the spiral, a is a constant, and θ is the angle of rotation in radians; means for orienting said antenna with and responsive to an electric field to generate currents therein, the currents in adjacent turns being in-phase and out-of-phase at predetermined radial positions of r and θ; resistive means proximate to at least one pair of said adjacent turns and coupled thereto in a region where the currents in the adjacent turns are out-of-phase; and detecting means coupled to the inner ends of said spiral antenna operative to measure the signal therebetween.
Claim 2
Dependent Claim
121 words
A microwave radiation monitor comprising: a dual Archimedean spiral antenna defined by r=aθ, wherein r is the radius from the center to a point on the curve of the spiral, a is a constant, and θ is the angle of rotation in radians; means for orienting said antenna with and responsive to an electric field to generate currents therein, the currents in adjacent turns being in-phase and out-of-phase at predetermined radial positions of r and θ; resistive means proximate to at least one pair of said adjacent turns and coupled thereto in a region where the currents in the adjacent turns are out-of-phase; and detecting means coupled to the inner ends of said spiral antenna operative to measure the signal therebetween.
Claim 3
Dependent Claim
32 words
A microwave radiation monitor as defined in claim 1, wherein said resistive means is positioned where r is substantially equal to one-half of the wavelength of a predetermined frequency to be monitored.
Claim 4
Dependent Claim
28 words
A microwave radiation monitor as defined in claim 1, wherein said resistive means comprises a film of resistive material separated from said coupled adjacent turns by insulation means.
Claim 5
Dependent Claim
21 words
A microwave radiation monitor as defined in claim 3, wherein said resistive means is proximate to a plurality of adjacent turns.
Claim 6
Dependent Claim
36 words
A microwave radiation monitor as defined in claim 1, wherein said detecting means comprises a diode connected across said inner ends of the spiral antenna and a meter connected to measure the current through said diode.
Claim 7
Dependent Claim
21 words
A microwave radiation monitor as defined in claim 5, wherein said meter is connected to said diode by high resistance leads.
Claim 8
Dependent Claim
24 words
A microwave radiation monitor as defined in claim 6, wherein said high resistance leads are tapered with the narrow end connected to said diode.
Claim 9
Dependent Claim
60 words
A microwave radiation monitor as defined in claim 5, wherein said diode is characterized by a capacitance that decreases as the reverse voltage across said diode increases, and comprising inductance means connecting said diode across said inner ends of the spiral antenna, the reactance of said inductance being selected to resonate with said capacitance when a predetermined frequency is monitored.
Claim 10
Dependent Claim
48 words
A microwave radiation monitor as defined in claim 6, including spaced contacts along one of said high resistance leads, and means to connect a properly polarized d-c voltage between said contacts, whereby said meter indicates at least a predetermined current flow when the components are in working order.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-01-02 | 1987-07-04 | 1988-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-02 | 1991-07-04 | 1992-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-02 | 1995-07-04 | 1996-01-03 | $7700.00 | Window Closed / Lapsed |