Investigation on self-jamming suppression in passive RFID when using multisines to enhance wireless power transfer

Multisine (MS) signals have been proposed in some works to extend the reading range of passive RFID systems. However, due to high crest factor, MS signals can exacerbate self-jamming effects in full-duplex passive RFID systems. This work investigates self-jamming suppression of MS signals. For this purpose, a bi-directional coupler has been constructed and combined with a suitable technique to cancel out Tx to Rx leakage in a MS-capable RFID reader. Measurements using static self-jamming suppression indicate a CW isolation (average) of 40.8dB, a MS isolation of 38.3dB, and an improved MS isolation of 66.3dB, when the suppression scheme is aided by a narrow band-pass filter.