A 1.6–2.2GHz 23dBm low loss integrated CMOS duplexer

This paper presents a tunable integrated electrical balanced duplexer as a compact alternative to multiple bulky SAW and BAW duplexers. A floating balancing network creates a replica of the TX signal for cancellation at the input of a single-ended LNA, thus enabling high power operation. It achieves around 50dB isolation within 1.6-2.2GHz range. The cascaded noise figure of the duplexer and LNA is 6.5dB, and the TXIL of the duplexer is about 3.2dB. The maximum achieved TX power is around 23dBm suitable for WCDMA transceivers. The duplexer and LNA are implemented in CMOS 0.18μm and occupy an active area of 0.35mm².