Useful measurement method of refractive indices in super high frequency electromagnetic wave region has been investigated by using coplanar waveguide (CPW) to achieve novel LC functional devices. However, inserted metal plate which acts as moving short dose not show stable propeties and rubbing effect is destroyed by the mechanical contacts in each measurement. In this work, a CPW is fabricated by using Si wafer and new measurement method is investigated by using optical short as a non-contact method.