A class of a planar triplexer by manipulating multiple attenuation poles

This paper focuses on a planar triplexer consisting of bandpass filters (BPFs) using different kinds of tapped resonators. The design methodology of proposed triplexer is established by using general filter theory with narrow hand approximation. The results show that the triplexer produces desired three passband, manipulation of multiple attenuation poles and good isolation characteristics without increasing the number of elements.