Design and comprehensive analysis of a novel structure of ARCL-to-SCL GSG transition for millimeter wave applications

A comprehensive study of air core recta-coax line (ARCL) based on MEMS surface micromachining technology is presented in this paper. The ARCL-to-semi-rectangular coaxial transmission line (SCL) ground-signal-ground (GSG) transition is proposed and designed for probe testing and integration with MMIC chips. To obtain the characteristic impedance of SCL, an equivalent model and theoretical derivation process is presented. In order to consider the effects of processing on performance, electrical effects of dielectric support strap parameters and potential fabri-cation issues including offset layers and over etching are investigated. For verification, the back-to-back GSG transition is fabricated and measured which has a low insertion loss of 0.13 dB up to 50 GHz, and a return loss better than -23 dB within 5-50 GHz. As an example, a demonstration of ARCL with GSG transition for MMIC chips integration is demonstrated.