Compact printed ultra-wide band filter employing SRR-DGS

A topology of compact planar microstrip ultra-wideband (UWB) bandpass filter (BPF) has been proposed and implemented in this paper. By employing split-ring resonator defected ground structure (SRR DGS), the BPF with good selectivity and out-of-band characteristics are obtained. U-slot DGS is also used to improve high frequency suppression. Simulated results are confirmed via experiment, showing good wideband filtering performance. The measured insertion loss is less than 1.6 dB, the return loss is more than 15 dB, and the variation of group delay is less than 0.5 ns throughout the most of pass band with suppression about 15dB in 11 GHz–20GHz.