Half-mode substrate integrated waveguide (HMSIW) directional filter with complementary split ring resonator (CSRR)

A novel directional filter based on half-mode substrate integrated waveguide (HMSIW) technology is presented in this paper. The directional filter consists of two identical HMSIW bandpass filters (BPFs) and two identical 3-dB couplers. The HMSIW BPFs were realized by etching complementary split ring resonators (CSRRs) on the top plane of HMSIW. The proposed directional filter was designed, fabricated and measured at K-band. The measurement results are obtained and agree with the simulation results.