Novel Compact Split Ring Stepped-impedance Resonator (sir) Bandpass Filters with Transmission Zeros

Abstract

Hairpin SIRs are novel structures with inner coupling which are implemented by the parallel coupling of transmission lines in the open-circuited port, and these structures not only can reduce more resonator dimensions but also increase the flexibility of filter design. In this paper, resonant characteristics of SIR are analyzed, and three types of novel compact split ring SIR bandpass filters, including two types of hairpin SIR bandpass filters with transmission zeros which operate at 2.3–2.8 GHz are proposed, and their filter performances are calculated and optimized. In these novel filter structures with nicer performances, hairpin SIRs and DGS techniques are applied to not only shorten the sizes but also suppress the spurious responses of filters. The filters presented in this paper have advantages such as compact, simple and novel structures, small sizes, high selectivity, wide stopband responses and so on.