Impact of super-isolation duplexer on SAW-less receiver RF front-end for cellular phones

This paper presents an antenna duplexer with a very high isolation in the Tx band for cellular handsets, and discusses its impact on a SAW-less receiver RF front-end. The developed duplexer has an isolation higher than 70 dB, which enables cellular transceiver RFICs to meet stringent linearity requirements without inter-stage SAW filters and sophisticated linearization techniques. The authors call such a highly isolated duplexer “super-isolation duplexer”. The progress of transceivers RFICs is also reviewed and the best solution for a SAW-less RF front end is considered.