Substrate-integrated waveguide matching terminations with microwave absorbing material

Substrate integrated waveguide (SIW) matching terminations or loads are proposed for low-cost integration in SIW circuits and systems. The principles of narrowband and broadband SIW terminations are demonstrated and discussed. Both narrowband and broadband terminations are optimised, fabricated and measured over the frequency range of 6-15 GHz. Relative frequency bandwidths (|S11| <; 20 dB) of the narrowband and broadband terminations are 7.6 and 42.6%, respectively. Good agreement between the measured and simulated results validates the feasibility of the proposed design strategies of SIW terminations.