Design of Wideband Coaxial-to-Substrate Integrated Coaxial Line (SICL) Planar Transition

Abstract

This article, presents a novel technique to model a wideband coaxial to substrate integrated coaxial line (SICL) transition. The proposed design is a planar implementation of the male to female connection usually observed in coaxial connections in conventional circuit. Firstly, a $50 \Omega$ SICL section is designed. The coaxial probe of equal impedance passing through a metallic via with slightly greater diameter is then connected to the inner conductor of SICL. The reactive component produced at the SICL-Coaxial junction is nullified by placing a short-circuit section at an optimal distance from it. The proposed transition demonstrates a broadband matching of greater than 20 dB for 0 to 32.7 GHz with very low insertion loss of better than 0.1 dB throughout the band. The complete modeling of proposed planar transition is presented and the robustness of the design is validated for different dielectric constant and thickness. The designed back to back transition exhibits wideband matching with very low insertion loss making it worthy for practical applications.