Design of a new dual-band diplexer for GPS, WLAN and WIMAX applications

摘要

In this paper, a dual-band diplexer is proposed. Two dualband bandpass filters (DB-BPFs) using coupled stepped-impedance resonators (SIRs) operated at 1.575/2.13 GHz and 3.15/5.2 GHz are main blocks combined with a branch matching circuit for the proposed dual-band diplexer. By analyzing the input impedance Z _(in) of different loading structures, we can precisely predict the stopband positions of the loading structures to avoid the interference between the two sets of different channels. A high isolation of 40 dB between the two sets of channels is obtained. The simulated and measured results have a good agreement with the proposed design concept.