Complementary split‐ring resonator for compact waveguide filter design

In this paper, the potential use of complementary split‐ring resonators (CSRRs) to design very compact waveguide filters, by etching a CSRR in the center of a metallic sheet, is demonstrated. This original layout reduces the dimensions of the well‐known resonant‐cavity waveguide filters coupled by irises. This has been made feasible due to the self‐resonance property of the CSRR. Thus, it is possible to design waveguide filters with lengths equal to the thickness of a metallic sheet. Consequently, this technique paves the way for the design of miniaturized waveguide filters, in contrast to conventional waveguide filters, based on bulk resonators.