Patent ID: 6948344

Claim:
A method of decreasing resonant frequency shifting of an electrical circuit of a transponder mounted on a substantially rigid vehicle key including a blade portion and a head portion, comprising the steps of: inserting the key and the transponder into a mold; injecting a substantially rigid, non-metallic material into the mold while the key and transponder are in the mold to form an undermold of said vehicle key, the undermold comprising a plurality of voids between the substantially rigid, non-metallic material and the transponder; supporting the transponder in the undermold; reducing forces produced on the electrical circuit by thermal expansion and contraction of at least one portion of the key by the plurality of voids between the substantially rigid, non-metallic material and the transponder, thereby decreasing resonant frequency shifting of said electrical circuit of said transponder; and overmolding said undermold, the transponder, and said one portion of said key with an overmold material.