Definition

Coplanar waveguide (CPW) is a transmission line structure where a signal trace is flanked by ground conductors on the same layer, with or without a ground plane below (grounded CPW, GCPW). CPW offers easy integration with surface-mount components since signal and ground are on the same surface. Impedance is controlled by the trace width and gaps to the coplanar grounds. GCPW provides better shielding and tighter impedance control. CPW transitions are common for RF probe testing and connector launches.