A CMOS Transmitter Leakage Canceller for WCDMA Applications

A transmitter (TX) leakage canceller is proposed for improving the dynamic range of the receiver (RX) for wideband code division multiple access applications. A TX leakage canceller circuit in this paper is simple in implementation and has low noise figure (NF) contribution. It is a feed-forward canceller that samples a reference signal from the TX output and injects the amplitude-adjusted and phase-rotated signal to the RX chain. The canceller circuit is integrated with a low-noise amplifier and implemented in a 0.18-
$\mu{\hbox{m}}$
CMOS technology. A cancellation of 23 dB is achieved with only 10-mA current consumption increase and low NF increase.