High isolation techniques for SAW duplexer modules

Isolation characteristics between transmitter and receiver ports for SAW antenna duplexer modules are studied in this paper. Two techniques for high isolation are presented. Optimized phase shifter conditions for SAW antenna duplexer modules at not 50 ohm cases have been analytically provided to achieve desired isolation performances. And switching circuit is proposed for high isolation characteristics. In order to confirm the prediction, obtained optimum phase condition and proposed circuit are applied to EGSM/DCS/ PCS triple band, SAW antenna duplexer modules.