A method is disclosed herein for tuning a responder unit (12). The method comprises the stops of storing energy in a responder unit energy accumulator (136) in a contactless fashion by RF energy transmitted from the interrogator unit (10) to the responder unit (12), and exciting within the responder...http://www.google.es/patents/US5491484?utm_source=gb-gplus-sharePatente US5491484 - Electronic transponder tuning circuitry
