Novel Multistub Loaded Resonator and Its Application to High-Order Dual-Band Filters

A novel multistub loaded resonator and its application to high-order dual-band bandpass filters are presented in this paper. A key merit of the filter configuration is that the characteristics of the second passband can be conveniently controlled, whereas that of the first passband are fixed. As the multistub loaded resonator contains six symmetric stubs, which can provide sufficient coupled sections between adjacent resonators, it is realizable to build the high-order dual-band filters using the proposed resonators. To illustrate the concept, two dual-band filters of third and sixth order are designed, fabricated, and measured. The measured results are in good agreement with the full-wave simulation results.