X-band 1/4λ dielectric-strip resonator filter

A novel quarter-guided-wavelength (1/4 lambda) dielectric-strip resonator (DSR) with one short-circuited end is proposed to design a compact and low-loss filter at X-band. One end of the DSR is metallised and then shorted to ground effectively to achieve a half-cut conversion from 1/2 lambda DSR. As a result, the resonator length is reduced by half while the unloaded quality factor (Q(u)) of the 1/4 lambda DSR only has a slight reduction as compared to the corresponding 1/2 lambda DSR. For demonstration, a third-order DSR bandpass filter centred at 10.45 GHz is designed, implemented and measured. Good agreement between simulated and measured results can be obtained, showcasing the advantages of compact size and low loss.