A Wideband DC Isolated Substrate Integrated Coaxial Line Transition for System Integration

Abstract

In this work, a wideband DC isolated substrate integrated coaxial line (SICL) transition for thick substrates is presented. The planar transition is devised utilizing a substrate truncated microstrip line as a transition to SICL section. Tapered slots etched on the top ground plane aid in improving the transition characteristics over a wide bandwidth. The DC isolation in the proposed transition is achieved by embedding a compact interdigital capacitor in a microstrip line connected to the SICL section. Performance of the transition with an embedded interdigital capacitor is analyzed. The proposed transition exhibits a fractional bandwidth of 22.37% with a measured mean insertion loss less than 1.2 dB in 9.09 GHz to 11.38 GHz band. The loss & group delay characteristics of the wideband transition are studied in this work. Development of DC isolated transition for the self-packaged & electromagnetically shielded SICL simplifies integration of active components for superior performance of the communication system.