Analysis of the mallet-like slotted-ground-plane resonator

The frequency response characteristics, such as resonance condition and spurious harmonic, of a mallet-like slotted-ground-plane resonator have been shown in this work. Unlike the conventional slotted-ground-plane resonator with a half wavelength, the length of this proposed structure is only quarter-wavelength long so that compactness can be achieved. The technique of size reduction for the resonator is furthermore presented by modifying the impedance ratio of the mallet-like slot segments. Owing to the semi-ground plane, decrease of the quality factor causes enhancement of the rejection bandwidth. We analytically derive design equations with respect to the impedance ratio of the mallet-like slot resonator and can predict resonant modes without utilizing EM simulation software. In addition, by utilizing the thru-reflect-line calibration technique and theoretical methods, parameter extraction of the equivalent circuit of the mallet-like open-slot resonator is presented.