Passive transponder for an RFID system, and method of transmitting data from/to a data source of such a passive transponder

摘要

A passive transponder includes an antenna, an antenna oscillator circuit and a data source. The antenna oscillator circuit is configured to operate at a first resonant frequency or at a second resonant frequency, depending on reception of energy at the transponder or on a data transmission from/to the data source.

主权项

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.