Towards mass production of Air Filled Substrate Integrated Waveguides (AFSIW) for ultra-low loss, broadband radar applications

The steadily increasing demand for higher data transmission rates leads to higher frequencies with greater bandwidth and at the same time reduced losses. The size of air-filled waveguides are frequency dependent, therefore an integration into a PCB is possible above 100 GHz in the D and G band region making them an interesting technology for 6G communication and radar application. Usually, substrate integrated waveguides (SIW) are manufactured in mass production with sidewalls made of Copper filled laser micro via fences. However, with these copper laser micro via fences used as sidewalls, losses can become excessive due to parallel plate mode excitation. Additionally, roughness of waveguide top and bottom walls must be minimized to reduce conductor losses. In order to meet the increased requirements of ultra-low loss, broadband signal transfer at D band we present an air-filled substrate integrated waveguide (AFSIW) technology with solid sidewalls and smooth top and bottom walls, which is suitable for mass production. In this paper, the AFSIW technology is proposed for ultra-low loss connections 140 GHz radar to connect IC's to antennas.