This paper presents a theoretical basis for millimeter-wave grounded coplanar waveguides (GCPW). Theory is applied to design GCPWs with printed circuit boards (PCBs) using conventional PCB fabrication techniques for microstrip-like ground-signal-ground (GSG) designs. Thermal properties are considered in the PCB construction including coefficients for thermal expansion (CTE), the dielectric constant (TCDk) and insertion loss (TCIL) as slight changes in dimension and dielectric characteristics can significantly impact performance at millimeter wave frequencies. The physical copper cladding roughness, the PTFE-glass construction and glass-weave effects, and the shoulder and lip shapes for plated-through holes in the copper cladding are also considered. Realized performance is compared to theory.