Integration of Passive D-Band Components Within the AFSIW Technological Platform for Future Systems on Substrate

This paper presents the integration of passive components at D-band (110-170 GHz) within the air-filled substrate integrated waveguide (AFSIW) technological platform. First, for interconnexion purposes, a wideband transition from WR-6.5 to AFSIW is introduced. It achieves a fractional bandwidth of 26.5 % with an average insertion loss (IL) as low as 0.85 dB. Then, the surface roughness losses at D-band of an AFSIW transmission line are studied in theory based on the Hurray model with an experimental validation. Finally, to demonstrate the interest of the AFSIW platform for the integration of passive functions, an AFSIW bandpass filter based on multi-mode and over-mode cavities is designed, simulated and fabricated. In experiment, it achieves a 23.5 % fractional bandwidth centered at 145 GHz with an average insertion loss of 0.95 dB.