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:
Oct. 05, 1999
Filed:
Dec. 05, 1997
Ming-Ren Lian, Boca Raton, FL (US);
Thomas P Solaski, Boca Raton, FL (US);
Sensormatic Electronics Corporation, Boca Raton, FL (US);
Abstract
An antenna system for an electronic article surveillance system, comprising: a first, tunable transmitting loop; a second, tunable transmitting loop, the first and second transmitting loops being arranged for first and second modes of operation, the transmitting loops being field-coupled to one another such that tuning the antenna system for one of the modes of operation detunes the antenna system for the other mode of operation; a tunable compensation coil field-coupled to each of the first and second transmitting loops, the tunable compensation coil enabling the antenna system to be tuned for operation in one of the modes at a first resonant frequency, and despite the detuning, enabling the antenna system to be tuned for operation in the other of the modes at a second resonant frequency independently of the tuning for the first mode of operation. The first and second resonant frequencies can be the same as or different from one another. One of the first and second modes of operation is as an in-phase rectangular loop and the other of the first and second modes of operation is as a 'figure-8'. The compensation loop encircles the first and second transmitting loops.