A compact wideband bandpass filter using triple-mode H-type resonator

In this paper, a new H-type triple-mode resonator is proposed to design a compact wideband bandpass filter. Due to the structure geometry, even-odd-mode analysis is applied to investigate the resonance conditions of the H-type resonator. To enhance the input/output coupling, an inter-digital coupling structure is adopted. A wideband bandpass filter is designed with a fractional bandwidth (FBW) of 80% to validate the design concept. The experiments are in good agreement with the simulations.