Self-Interference Cancellation Circuit With Improved Transmission Power Efficiency Based On Unequal Power Divider

The paper proposes a self-interference cancellation (SIC) architecture based on unequal power divider. The transmission efficiency of SIC is investigated. A power divider with unequal power dividing ratio is used in the SIC for improving transmission efficiency of circulator isolated transceiver. A four-tap SIC circuit was designed and fabricated. Measurement results show that 60dB isolation is achieved in the frequency band of 915-926MHz, which is an increase of 37dB compared to that of the original circulator. The transmission efficiency (TE) increases from 42.5% (power-dividing ratio is 1:1) to 69.1% (power-dividing ratio is 1:4).