A compact CSRR- based dual-mode patch bandpass filter

Abstract

A compact square patch bandpass filter is proposed in the paper. The dual-mode filter uses a square patch resonator with a complementary split ring resonator (CSRR) split as a perturbation element. The CSRR split is embedded in the square patch resonator to perturb field distribution and excite degenerate modes. Using the CSRR structure, the bandpass filter is miniaturized and two transmission zeros in stop-bands are achieved to improve the selectivity of the filter. The impact of the CSRR structure on the band-pass filter is analyzed in detail.