Design of a packaged microstrip triplexer with star-junction topology

A planar microstrip triplexer with compact size is proposed in this paper. The triplexer is composed of three pairs of bandpass filters and a star-junction. Specifically, the bandpass filters are constructed by stepped hair-pin resonators; the coupled feeding is applied to the star-junction, where bandpass filters are connected. Consequently, three passbands will be generated and a wideband insertion loss will be obtained. Furthermore, the triplexer can be integrated into an off-the-shelf package for frequency-division triplex wireless communication systems. In addition, the good agreement between measurement and simulation validates the feasibility of the configuration.