Miniaturised bandpass filter using dumb-bell-shaped slot resonator

A microstrip dumb-bell-shaped slot resonator (DSSR) is proposed for a miniaturised bandpass filter (BPF) design. An equivalent circuit model of the DSSR is also presented and validated through circuit and EM simulations. The proposed DSSR does not employ ground slots, so the fabrication process is simple. This ultimately results in an easy analysis and design which minimises fabrication errors. Using the DSSR, a miniaturised 7.35 GHz BPF is designed and tested. The filter dimensions are 0.37 g×0.27×g, where λg is the guided wavelength at the centre frequency of 7.35 GHz.