Defected and floating ground structures for vertical interconnects are investigated up to the E-band. For quasi symmetrical microstrip-to-microstrip (MS-to-MS) transitions the effect of shape and size of ground plane cutouts is studied. In addition, floating ground pads are proposed to enhance the matching of asymmetrical microstrip-to-stripline (MS-to-SL) transitions. All examined interconnects are quite insensitive to the influence of the environment and can thus be used in densely packed multilayer applications. The agreement between simulation and measurements confirms the concepts.
