Mode suppressing coplanar waveguide transition and method

摘要

A series capacitance is included in both surface ground conductors of coplanar waveguide on an MMIC die. The capacitance compensates for the inductance of bond wires used for transitioning from microstrip line to coplanar waveguide. The capacitance is chosen to resonate with the inductance of the bond wires at the desired frequency. As a result, virtually all microstrip mode ground signal currents are transitioned from the ground plane of the microstrip line to the surface ground conductors of the coplanar waveguide. Microstrip modes affecting the coplanar waveguide are significantly reduced improving isolation between ports of the MMIC die.