Novel hybrid resonant structures and its applications in compact multiband bandpass filters
A 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 0.14?0  0.11?0.  2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:690696, 2014.
hybrid resonant structure multiband bandpass filters dual-mode defected ground structure resonators