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

This paper 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 radiofrequency 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 fulfil 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 together with a transmission line model to provide 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 as low as 0.135 +/- 0.015 dB and 0.3 +/- 0.18 dB, respectively.