US4302846A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Marker tag for a detection system
Assignee: Individual
•
Filing: 1978-04-24
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Granted: 1981-11-24
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Expires: 1998-04-24
Abstract
Abstract This invention is directed to a receptor reradiator for use in a system for detecting the position of the receptor reradiator in a surveillance zone. It comprises a first aerial means for receiving the first signal, second aerial means for radiating said reply signal and a non-linear element coupling the first and second aerial means.
Inventors
- 👤 James H. Stephen
- 👤 John D. McCann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 00:12
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/22; G08B13/24; G08B13/2402; G08B13/2405; G08B13/2422; G08B13/2428; G08B13/2431; G08B13/2465; G08B13/2468; G08B13/2471; G08B13/2477
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
166 words
A receptor reradiator for use in a system for detecting the position of said receptor reradiator in a surveillance zone, the system transmitting a first frequency signal f 1 and a second frequency signal f 2 , so that said first and second signals define a center frequency f c =(f 1 +f 2 )/2, comprising: a dipole antenna having two metal conductive arms of a total length slightly less than half the wave length of the center frequency signal f c , said two arms coming together at a point defining the electrical center of the dipole; a non-linear semiconductor element disposed in one of said arms and offset from the electrical center of said dipole; and a parallel combination of a capacitance and inductance inserted in the arm containing the semiconductor element and tuned to receive said first and second frequency signals, so that said non-linear semiconductor element causes said dipole to reradiate an intermodulation signal generated by the first and second RF signals.
Claim 2
Dependent Claim
166 words
A receptor reradiator for use in a system for detecting the position of said receptor reradiator in a surveillance zone, the system transmitting a first frequency signal f 1 and a second frequency signal f 2 , so that said first and second signals define a center frequency f c =(f 1 +f 2 )/2, comprising: a dipole antenna having two metal conductive arms of a total length slightly less than half the wave length of the center frequency signal f c , said two arms coming together at a point defining the electrical center of the dipole; a non-linear semiconductor element disposed in one of said arms and offset from the electrical center of said dipole; and a parallel combination of a capacitance and inductance inserted in the arm containing the semiconductor element and tuned to receive said first and second frequency signals, so that said non-linear semiconductor element causes said dipole to reradiate an intermodulation signal generated by the first and second RF signals.
Claim 3
Dependent Claim
27 words
A receptor reradiator as claimed in claim 1 wherein said semiconductor element and dipole arms comprise a cuprous oxide semi-conductor connected between a pair of copper electrodes.
Claim 4
Dependent Claim
30 words
A receptor reradiator as claimed in claim 1 wherein said semiconductor element and dipole arms comprise a cuprous sulphide on cadmium sulphide semi-conductor connected between a pair of copper electrodes.
Claim 5
Dependent Claim
26 words
A receptor reradiator as claimed in claim 1 wherein said semiconductor element and dipole arms comprise a selenium semi-conductor connected between a pair of copper electrodes.
Claim 6
Dependent Claim
28 words
A receptor reradiator as claimed in claim 1 wherein said semiconductor element and dipole arms comprise a titanium dioxide semi-conductor between a titanium electrode and a silver electrode.
Claim 7
Dependent Claim
29 words
A receptor reradiator as claimed in claim 1 wherein said semiconductor element and dipole arms comprise a lead sulphide semi-conductor connected between a pair of copper or aluminium electrodes.
Claim 8
Dependent Claim
29 words
A receptor reradiator as claimed in claim 1 wherein said semiconductor element and dipole arms comprise a magnesium oxide semi-conductor connected between a magnesium electrode and an aluminium electrode.
Claim 9
Dependent Claim
31 words
A receptor reradiator as claimed in claim 1 wherein said semiconductor element and dipole arms comprise a aluminium (AL 2 O 3 ) semi-conductor connected between a pair of aluminium electrodes.
Claim 10
Dependent Claim
27 words
A receptor reradiator as claimed in claim 1 wherein said semiconductor element and dipole arms comprise a zirconia (ZrO 2 ) on zirconium connected between aluminium electrodes.
Claim 11
Dependent Claim
29 words
A receptor reradiator as claimed in claim 1 wherein said semiconductor element and dipole arms comprise a gallium arsenide semi-conductor connected between a pair of gold or aluminium electrodes.
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) | 1984-11-23 | 1985-05-25 | 1985-11-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-23 | 1989-05-25 | 1989-11-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-23 | 1993-05-25 | 1993-11-24 | $7700.00 | Window Closed / Lapsed |