Patent ID: 8260241

Claim:
A Radio Frequency Identification (RFID) reader comprising: a transmit circuit adapted to transmit a first radio frequency (RF) signal; a receive circuit adapted to receive a second RF signal; a self-jammer cancellation circuit adapted to: receive a third RF signal associated with the first RF signal, receive a self-jamming signal associated with the first RF signal, wherein the self-jamming signal is a portion of the second RF signal, generate at least two distinct phase variants of the third RF signal, select two of the distinct phase variants, wherein a vector projection of a first of the selected phase variants on a second of the selected phase variants is substantially greater than zero, and wherein a canceling signal comprising a combination of the selected phase variants is substantially opposite in phase to the self-jamming signal, select amplitudes for each of the two selected phase variants such that the canceling signal is substantially equal in amplitude to the self-jamming signal, and combine the canceling signal with the second RF signal to reduce an amplitude of the self-jamming signal portion of the second RF signal.