The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 04, 2000
Filed:
Aug. 07, 1997
Ian James Forster, Chelmsford, GB;
GEC-Marconi Communications. Ltd, Middlesex, GB;
Abstract
An interrogator circuit (2) for use with a semi-passive transponder (30) of a type which reflectively modulates an incoming signal (28) is described. The circuit (2) comprises an antenna (4), a transistor (8), a matching network (6) connecting to the antenna (4) to an input of the transistor and means (12, 14) for operating the transistor such that it self-oscillates and radiates power (28) from the antenna (4) and simultaneously acts as a self-oscillating mixer to produce an output (40) which is representative of the modulation of a signal 32 received at the antenna. For an efficient conversion gain the reflection coefficient of the antenna (4) is configured to be low when the circuit is in a stable self-oscillating condition.