A Compact Dual Mode Diplexer for Wireless Applications

Abstract

A diplexer circuit for CDMA and Bluetooth application is reported in this paper. Stub-loaded dual mode resonator is characterized here from theoretical and full-wave simulation and found that even mode and one transmission zero frequency can be flexibly controlled for a fixed odd-mode frequency. Based on the principle of dual-mode stub loaded resonators, a compact diplexer circuit with sharp selectivity factor and high isolation has been designed and validated through measured results. The designed diplexer has insertion loss and reflection loss better than 2dB and 10dB respectively in the operating band.