| US 7,592,961 B2 | ||
| Self-tuning radio frequency identification antenna system | ||
| Dario Sassi Thober, Alphaville (Brazil); Wellington de Oliveira Giolo, Campinas (Brazil); Jerome Breche, Huntsville, Ala. (US); Thiago Cardoso, Alphaville (Brazil); Alecio Fernandes, Alphaville (Brazil); and Ademir Xavier, Alphaville (Brazil) | ||
| Assigned to Sanimina-Sci Corporation, San Jose, Calif. (US) | ||
| Filed on Feb. 16, 2006, as Appl. No. 11/357,679. | ||
| Claims priority of provisional application 60/729281, filed on Oct. 21, 2005. | ||
| Prior Publication US 2007/0091006 A1, Apr. 26, 2007 | ||
| Int. Cl. H01Q 1/38 (2006.01) | ||
| U.S. Cl. 343—745 [343/750; 343/860; 343/861] | 12 Claims |
| 1. A self tuning antenna comprising:
a main antenna;
an impedance compensation circuit coupled to the main antenna to vary the input impedance of the main antenna; and
a controller coupled to the main antenna and impedance compensation circuit to automatically determine when an impedance mismatch
occurs on the main antenna and automatically adjust the impedance compensation circuit to minimize the impedance mismatch,
wherein the impedance compensation circuit includes a digital variable capacitor that is adjusted by the controller to minimize
impedance mismatch, the digital variable capacitor includes a plurality of individually controllable parallel plate capacitors
that are added or removed from the impedance compensation circuit by the controller.
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