High isolation SAW antenna duplexer modules

摘要

An optimized phase shifter condition for the SAW antenna modules has been provided to achieve high isolation performances when the load impedance is not characteristics impedance. In the EGSM/DCS dual band antenna duplexer modules, impedances of low noise amplifiers connecting the Rx ports are not characteristics impedance when the amplifier switches are off state at transmitter period. We propose optimized phase shifter circuits for EGSM Rx output ports. Isolation improvement of 6 dB is obtained in this case. In the Japanese cdmaOne duplexer, we propose an optimized phase shifter circuit for the transmitter circuit between Rx band trap and transmitter top filter block. Isolation improvement of 1 to 3 dB is obtained in this case.