The designed triplexer has three channels, from 0.8 to 1 GHz for GSM/CDMA, from 2.4 to 2.5 GHz and from 4.9 to 5.8 GHz, for WLAN separately. It has low insertion loss, good return loss, high isolation, low ripple in each passband. Measurement results of the fabricated triplexer are shown to match well with the electromagnetic simulation, which validate the proposed structure. Key words: Triplexer, multi-mode/multi-band, dual-band, stepped-impedance resonators (SIRs)

Ⅰ. Introduction

In recent years, the wireless communication systems, such as the cellular mobile communication systems (CDMA, GSM, WCDMA, TD-SCDMA), the wireless local area networks (WLAN), the short range communication systems (Bluetooth, UWB), provide convenient communication services in modern society. In an airplane, when the onboard wireless communication services are provided, many different systems may be used simultaneously. Compact equipments that support multi-mode/multi-band wireless systems are very attractive and will be widely used in the future. Among them, a multiplexer is an important component of the transceiver for modern wireless or mobile communication systems. It combines with the multi-mode/multi-band wireless systems and the ultra wide band antenna. Therefore the performance of the triplexer has a direct impact on the whole system.