Compact W-Band Shielded Asymmetrical Coplanar Stripline To Microstrip Transition For Millimeter-Wave Applications

This paper presents a compact W-band shielded asymmetrical coplanar stripline (SACPS) to microstrip transition for millimeter-wave applications. The SACPS consists of an asymmetrical coplanar stripline (ACPS) and a metal shielding cavity, and can propagate quasi-TEM mode. For the microstrip line, its strip and ground conductors are at toplayer and bottomlayer, respectively. Hence, the principal step is to convert the ground plate from the toplayer to bottomlayer, which becomes the defected ground microstrip. Then, a defected ground microstrip to microstrip transition is built with a impedance matching section. For purpose of measurement, a transition between microstrip and rectangular waveguide WR-10 is added. Finally, two SACPS-microstrip-rectangular waveguide transitions are connected with a back-to-back structure. Over the entire 75-110 GHz range, the simulated and measured insertion losses are less than 0.6 and 1.5 dB, respectively, while simulated and measured return losses are better than 15 and 10 dB, respectively.