A method of decreasing resonant frequency shifting of an electrical circuit mounted on a vehicle key includes providing a frame in an opening in the head portion of a vehicle key and locating the transponder in the frame. The frame comprises substantially rigid non-metallic material, and the frame includes a support structure for supporting the transponder while decreasing forces produced on the transponder by thermal expansion and contraction of the head portion of the key, thereby decreasing shift in the resonance of the electrical circuit of the transponder. The frame, the transponder and the head portion of the key are overmolded providing an outer covering that encloses and protects the transponder.