Design of the SISL Waveguide Filter With Co-Designed Magnetic-Coupled SISL Resonators Using Hybrid SISL and AF-SIW Technologies

This letter presents the design and implementation of a new class of substrate-integrated suspended line (SISL)-based waveguide filters (SISLWFs) based on the magnetic-coupled SISL resonators (MCRs). Cavity resonators excited by the SISL via are utilized to design the passband while the $0.5~\lambda _{g}$ SISL shorted stub line (SISLSS) resonator printed on G5 layer is directly connected to the SISL via to generate transmission zeros (TZs). A magnetic-coupled $0.5~\lambda _{g}$ L-shaped short-ended resonator (LSR) is also printed on the G5 layer and arranged at the end of the SISLSS to generate a new TZ. By utilizing the novel short-ended MCR topology, more SISL resonators can be co-designed in the SISL cavity, thus, up to seven TZs can be generated and controlled simultaneously. The measured results coincide well with the simulated ones which validates the proposed MCR methods.