The　unipolar,　bipolar,　and　quadrupolar　coils　used　in　an　electric　vehicle　wireless　charging　system　are　not　interoperable　with　each　other.　Thus,　there　would　be　interoperability　issues　when　the　transmitting　and　receiving　coils　are　not　the　same.　To　solve　this　issue,　in　this　letter,　we　propose　an　asymmetrical　quadrupolar　coil　that　can　be　interoperable　with　the　four　conventional　coils　at　the　same　position　for　efficient　wireless　power　transfer,　namely　the　unipolar　coil,　the　bipolar　coil　along　two　perpendicular　directions,　and　the　quadrupolar　coil.　Large　coupling　coefficients　can　be　achieved　for　the　proposed　coil　with　the　four　conventional　coils　when　perfectly　aligned.　The　misalignment　performance　with　the　four　conventional　coils　is　also　investigated.　An　experimental　prototype　is　developed　to　compare　the　conventional　symmetrical　quadrupolar　coil　with　the　proposed　asymmetrical　quadrupolar　coil　for　validation　of　interoperability.　The　proposed　asymmetrical　quadrupolar　coil　achieves　a　maximum　coupling　coefficient　of　over　0.10　and　a　maximum　dc-dc　efficiency　of　over　85%　with　the　four　conventional　coils.　©　1982-2012　IEEE.