3-pole bandpass filters using short-ended half-wavelength resonators and their applications to a duplexer

The paper presents bandpass filters (BPFs) using short-ended half-wavelength resonators for out-of-band rejection and their applications to a duplexer. BPFs with out-of-band rejection are provided. Finally, we propose and design the new duplexers consisting of the proposed BPFs. The results of this study lead us to the conclusion that our proposals about the BPF and the duplexer are useful for realizing good characteristics without increasing the number of elements.