Patent ID: 8073548

Claim:
A sensor system, comprising: a sensor, adapted to be implanted in a subject, wherein the sensor is configured to measure one or more aspects of the subject and wherein the sensor comprises a sensor antenna; a sensor reader configured to provide power to the sensor, wherein the sensor reader is adapted to be worn by the subject and comprises: (i) a reader housing containing an electronic circuit; (ii) a reader antenna for coupling with the sensor antenna, wherein the reader antenna is electrically coupled to the electronic circuit, forms a coil having at least one turn when wound completely around a body part of the subject, is adjustable in size to any of a plurality of adjustment sizes, and is used by the sensor reader while the at least one turn of the coil is wound completely around the body part of the subject to provide power to the sensor; and (iii) a plurality of tuning elements each associated with a different size of the plurality of adjustment sizes; wherein the reader antenna has a resonant frequency and the plurality of tuning elements keep the resonant frequency of the reader antenna substantially unchanged regardless of the adjustment size to which the reader antenna is adjusted.