Wideband Transition from Coplanar Waveguide to Microstrip-line for Liquid Crystal Loaded Microwave Device

摘要

A new wideband transition from coplanar waveguide to microstrip-line utilizing electric contact is proposed for microwave applications using liquid crystal. Design guideline for liquid crystal loaded microstrip-line section and coplanar waveguide to microstrip-line transition section, which are based on simulations and experimental results, are discussed. Simulation and experimental results agreed well each other and demonstrated broadband performance and low insertion loss. The transition provides insertion loss less than 1.5 dB and return loss of about -10 dB for frequency range from DC to 30 GHz. A liquid crystal loaded microwave phase shifter is also designed based on this transition structure and shows good performances.