Design of Compact Inline Triplexer for Multi Band Receiver

This paper reports the design of a novel compact inline triplexer for multi band wireless transceivers. In the proposed triplexer, three band pass filters are coupled tightly to a common feeding line in an inter digital configuration. Each of the band pass filter is independently designed along with the adequate overlapping isolation structures. Each band pass filter is designed to have at least one transmission zero in the other bands of operation thus resulting in proper isolation. This way of designing band pass filters resulted in compactness. A prototype triplexer operating at frequencies 2.3GHz, 3.4GHz and 5.6GHz has been developed and tested. The 1.0-dB bandwidth in each band is approximately 8.9% for all the three bands. Measured results are in good agreement with the full wave EM simulation results.