Consistent and Cost-Effective PCB-Based D-Band Air-Filled Substrate-Integrated-Waveguide Filters

Only a limited amount of research has been performed on the implementation of air-filled substrate-integrated-waveguide (AFSIW) systems in multi-layer PCB stacks at subterahertz frequencies. In this paper, we investigate the manufacturing reliability and the measurement repeatability based on several measurements of AFSIW transmission lines and three different filters on three separate PCB panels at D-band frequencies (110 GHz-170 GHz). A promising dual-cavity AFSIW filter with a steep roll-off on both sides of the passband is designed, fabricated and measured. The measured insertion loss is around 3 dB, while the out-of-band suppression is better than 30 dB.