Design and simulation of triplexer for mobile communications using trisection resonators filters

This paper presents a microstrip triplexer with multiband performances by using cascaded trisection (CT) filters. Each CT section is composed by three directly coupled resonators with a cross coupling. The cross coupling produces a single attenuation pole at the finite frequency. Furthermore, each trisection filter controls a specific channel frequency independently. To obtain good isolation response, the resonators are properly located with respect to the input and output feeding lines to suppress the channel interfering and meet the design specifications for mobile communications.