Optimized phase shifter conditions for SAW antenna duplexer modules at not 50 ohm cases have been analytically provided to achieve desired isolation performances. In order to confirm the prediction, obtained optimum condition are applied to two cases. In the EGSM/DCS dual band SAW antenna duplexer modules case, impedances of low noise amplifier connecting the Rx ports are not 50 ohm when the amplifier are off state at transmitter period. We propose a optimized phase shifter circuit for EGSM and DCS Rx output ports using the equation. In Japanese cdmaOne duplexer case, we also propose an optimized phase shifter circuit for the transmitter circuit between Rx band trap and transmitter top filter block. The predictions are verified by the experiments.
ASJC Scopus subject areas
- Acoustics and Ultrasonics