A fast active leakage cancellation method for UHF RFID readers

Abstract

In this work, a fast method for vector modulation based active leakage cancellation is proposed for UHF RFID readers. The search space is narrowed by an initial phase and amplitude comparison between the reference signal and the leakage signal. The proposed method achieves up to 32% reduction in the number of search steps with up to 60 dB suppression in the leaked signal power. Moreover, the settling time can be further reduced by putting an upper limit on the residual leakage power so that the search will be terminated once the residual leakage drops below a predefined value. By this way, up to 69% reduction in the number of search steps and up to 39% reduction in settling time can be achieved by setting the limit at −50 dBm.