New phase-shifter and LNA for self-interference suppression in full-duplex communication system

Full-duplex wireless communication is deemed to have remarkable application prospect for the possibility in enhancing the spectrum efficiency by 2 times. However, the strong transmitted leakage signal causes serious self-interference for the full-duplex system. To address this question, a new sectional type full-360° phase-shifter and a gm-tunable LNA are proposed for the feed-forward self-interference suppression, which provide fine phase and amplitude tuning precision smaller than 0.5° and 1.5dB respectively. Moreover, a noise attenuator factor is introduced in the LNA for noise reduction. The NF of the proposed LNA is 6.3dB and the effective signal gain is 18.3dB. Benefited from the proposed phase-shifter and LNA, the self-interference suppression depth is larger than 32dB, which demonstrate the effectiveness of the proposed circuits for self-interference suppression for RFID or other full-duplex wireless communication systems.