Definition

Grounded coplanar waveguide (GCPW), also called conductor-backed coplanar waveguide (CBCPW), combines coplanar ground isolation with traditional ground-plane referencing. A signal trace is flanked by ground conductors on the same layer (ground-signal-ground), with an additional ground plane on the opposite side of the substrate. GCPW extends the usable frequency range of FR-4 because most of the field travels between the trace and coplanar grounds through air rather than the lossy laminate. For flex circuits, GCPW keeps return paths on the same layer as signals, avoiding a stiff mechanical I-beam structure that resists bending.