an electromagnetic wave energy seal arrangement for a microwave oven which incorporates juxtaposed conductive surfaces spaced apart by a gap which circumscribes the perimeter of an access opening to the oven cooking cavity . one of the conductive surfaces is located on the oven door , overlies a recessed channel in the door , and is provided with slots to inhibit longitudinal currents . the slots are configured to have a first average width near the slot entrance and a second larger average width adjacent the slot terminus to thereby better tailor the bandwidth of the slots for optimum operation to the specific microwave energy characteristics of the oven .