| US 7,570,220 B2 | ||
| Resonant circuit tuning system with dynamic impedance matching | ||
| Stewart E. Hall, Wellington, Fla. (US); Richard Herring, Wellington, Fla. (US); and Guillermo Padula, Boca Raton, Fla. (US) | ||
| Assigned to Sensormatic Electronics Corporation, Boca Raton, Fla. (US) | ||
| Filed on Jun. 27, 2006, as Appl. No. 11/475,771. | ||
| Prior Publication US 2007/0296593 A1, Dec. 27, 2007 | ||
| Int. Cl. H01Q 9/00 (2006.01) | ||
| U.S. Cl. 343—745 [343/867; 340/572.7] | 6 Claims |
| 1. A resonant circuit tuning system comprising:
a resonant circuit having a first capacitive element in series between a transmitter and an antenna coil and a second capacitive
element in parallel with the transmitter and the antenna coil, at least one of the first capacitive element and second capacitive
element configured to be varied;
a controller for controlling a variable value of at least one of the first and second capacitive elements; and
a variable inductive element connected in one of (i) a series arrangement with the antenna and (ii) magnetically coupled to
the antenna.
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