Multilayer GCPW-to-AFSIW Transition for High-Performance Systems on Substrate

This letter presents a transition from a top layer grounded coplanar waveguide (GCPW) to an inner layer air-filled substrate-integrated waveguide (AFSIW). Such type of transition is crucial for the interconnection of top layer surface-mounted radio-frequency integrated circuits (RFICs), toward the integration of complete microwave and millimeter-wave systems taking advantage of the low-cost and high-performance AFSIW technological platform. To fulfill the new space application needs, the proposed transition has been developed in the satellite downlink Ka-band ranging from 27.5 to 31 GHz. The structure is detailed with design guidance. For experimental evaluation, a back-to-back prototype has been fabricated and measured. In the operating frequency range, the proposed transition achieves a simulated and measured insertion loss (IL) as low as 0.135 ± 0.015 dB and 0.3 ± 0.18 dB, respectively.