Novel nested split-ring-resonator (SRR) for compact filter application

Abstract

In this paper, a novel miniaturized nested split-ring resonator (SRR) structure is proposed. The nested SRR structure incorporates multiple split-ring resonators in a compact nested structure, and has more split gaps than the conventional SRR structure. Compared with conventional SRR, this nested SRR has better performance on miniaturization and high-Q value. To verify good characteristics of the proposed resonator structure, a novel resonator-embedded band-pass filter (BPF), which is constructed by four nested resonators, is designed. This novel BPF is very compact and has good in- and out-band performances. The proposed nested SRR unit cell has size of 0:04λg × 0:04λg (λg is the signal wavelength at the 2.4 GHz central frequency of the pass-band). Its stop-bands are extended 0:5 ~ 2 GHz at lower band and 2:7 ~ 5:4 GHz at upper band with a rejection level of higher than 20 dB, and its 1-dB pass-band is 2:2 ~ 2:55 GHz with 1.8 dB optimized insertion loss. The measured and simulated results are well complied with each other.