Patent ID: 8749358
Filing Date: 2014-06-10
Classification: H02J,H03J

Abstract:
1. A passive transponder for an RFID system, comprising: an antenna; an antenna oscillator circuit; and a data source; wherein the antenna oscillator circuit is configured to: operate at a first resonant frequency to store, in the antenna oscillator circuit, energy received by the passive transponder; and operate at a second resonant frequency to generate, using only the energy stored in the antenna oscillator circuit, a data transmission signal at the second resonant frequency for a data transmission from the data source; wherein the antenna oscillator circuit includes a capacitive assembly and an inductive assembly; at least one of a capacitance value of the capacitive assembly and an inductance value of the inductive assembly is variable to switch the antenna oscillator circuit from the first resonant frequency to the second resonant frequency; and a controller is provided and programmed to change the capacitance value of the capacitive assembly if a predetermined portion of the energy stored within the antenna oscillator circuit is stored within the inductive assembly.