A compact microstrip step-impedance low-pass filter (SILPF) using complementary split ring resonators (CSRRs)

A new topology for the design of microstrip low pass filters (LPF) with a wide stopband, low insertion loss, and sharp rejection is proposed in this paper. This filter is especially relevant for Wireless Sensing, Local Positioning, and RFID. In this contribution, the concept of complementary split ring resonators (CSRRs) is utilized to improve the selectivity of a microwave low pass filter. To this end, a step-impedance low-pass filter (SILPF) with CSRR is first analyzed and then built. Properties of these configurations are discussed, and two manufactured prototypes have been successfully tested. The results show the usefulness and validity of the new structures with high rejection capabilities.