Novel hybrid resonant structures and its applications in compact multiband bandpass filters

AbstractA novel hybrid resonant structure which can realize compact multiband bandpass filters BPFs and its design method are proposed in this article. The hybrid resonant structure is a dual-plane structure which is an effective combination of a pair of microstrip stepped impedance resonators on the top layer and two nested dual-mode defected ground structure resonators on the bottom layer. A triband BPF adopting this hybrid resonant structure was presented which was operating at 2.4/5.7 GHz wireless local area network application and 3.5 GHz worldwide interoperability for microwave access application. The size of this filter is only 0.14λ0 × 0.11λ0. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:690-696, 2014.