A Novel Miniaturized Dual-Passband Half-Mode Substrate Integrated Waveguide Filter Loaded with Back-to-Back CSRR

In order to solve the requirements of multi-channel communication applications, this paper proposes a miniaturized dualpassband substrate integrated waveguide filter with asymmetric passband response. The design uses a half-mode substrate integrated waveguide (HMSIW) cavity, which is loaded with a back-to-back complementary open resonant ring (CSRR) according to the vanishing mode propagation theory to generate a passband response lower than the HMSIW basic mode TE101, further reducing the cavity size. In addition, the band-resistive characteristics of the single-ring structure of the CSRR resonator are analyzed, and a C-slot is added at the feeder to improve the out-of-band characteristics of the second passband. Through simulation optimization and testing, the center frequency of the dual-passband filter is 4.05 GHz/8.64 GHz; the relative bandwidth is 16%/44%, the insertion loss of both passbands is better than 0.8 dB; the physical test results are consistent with the simulation ones; and the size of the filter is only 0.42λg × 0.14λg. It shows that the proposed filter has the characteristics of small size and low loss, and can be widely used in multi-channel RF front-end systems in the field of wireless communication. © 2024, Electromagnetics Academy. All rights reserved.