A microstrip three-port and four-channel multiplexer for WLAN and UWB coexistence

This paper proposes a microstrip three-port four-channel multiplexer for wireless systems where wireless local area network (WLAN) and ultra-wideband (UWB) coexist. The proposed multiplexer has two channels, from 2.15 to 2.89 GHz and from 5.13 to 5.84 GHz, for WLAN and two channels, from 3.22 to 4.83 GHz and from 6.07 to 8.22 GHz, for UWB. The measured scattering parameters agree well with the simulations. To determine a proper circuit topology and overcome the interference problems between ports, the genetic algorithm (GA) technique is exploited. The GA search takes approximately 3 min on a personal computer with a 2.4-GHz microprocessor. Additionally, the analysis of the circuit behaviors, the problem on the size of the multiplexer, and the isolation issues between WLAN and UWB ports are discussed.