Demodulator for multi-carrier UHF RFID tags

A multi-carrier UHF RFID system provides the required power of a passive tag via multiple carriers. It is proved that the method can effectively extend the tag access range since the tag operating power is almost always satisfied. However, the extension is confined due to waveform distortion of reader command at the tag´s demodulator. This work discusses this problem and proposes a solution by adding an additional bandpass filter before the envelope detector. Computer simulation results show that the proposed solution effectively mitigates the demodulation problem.