This paper presents a ferroelectric varactor shunt switch which can be useful for microwave/millimeterwave switching as well as for the design of reconfigurable circuits. The device operation is based on nonlinear dielectric tunability of a ferroelectric thin-film sandwiched between two metal layers in the parallel plate configuration. A CPW based design allows for MMIC compatible shunt switches with low insertion loss and high isolation. Experimental performance of the varactor shunt switch indicates good switching performance with ~24 dB isolation @41 GHz, and insertion loss below 7 dB up to 45 GHz.