transmission line layout pcell in cadence

Hi all
Cadence provides CPW(Coplanar waveguide) schematic and layout pcell. But in the Pcell there is
a port called vshield besides input and output ports.Does anyone know where
should the shield port be connected?Thank you very much.

As for most transmission line elements, the third terminal usually goes to ground. I've also seen people do floating shield for passives, but I doubt the cadence pcell will capture that effect.