Feeding topologies for half-mode substrate-integrated waveguide bandpass filter

Two novel feeding structures for half-mode substrate-integrated waveguide are proposed in this letter. A bending coupled-line bandpass filter (BPF) by magnetic coupling and a bending coupled-line BPF by electric coupling are presented based on the respective coupling structures. By observing the cavity field distributions, magnetic coupling or electric coupling between the feeding line and cavity is investigated. Two BPF prototypes are designed and tested to validate the design concept with good agreement.