Microwave energy oven seal

Claim 1

Heating apparatus comprising: an enclosure; means for energizing said enclosure with electromagnetic wave energy predominantly adjacent a predetermined operating frequency; said enclosure comprising a wall member having an access opening communicating with said enclosure; a door for closing said opening; an energy escape seal comprising at least portions of said door and access opening peripheral walls and forming a propagation path for said energy extending from a first region adjacent to the interior of said enclosure and to the peripheral edges of said opening to a second region outside said seal; said seal having a first dielectric loaded frequency responsive structure coupled to said path comprising first substantially low impedance means electrically spaced a distance substantially equal to an integral number of one-half wavelengths at said operating frequency from said first region and a second portion of said path communicating with the first path portion and defined at least in part by opposing adjacent wall surfaces of said door and wall members when said door is closed; said second path portion terminating at said second region adjacent to the outer peripheral edges of said door; a second dielectric loaded frequency responsive structure coupled to said second path comprising second substantially low impedance means electrically spaced from said second region by a distance substantially equal to an integral number of half wavelengths of said frequency; and said first and second frequency responsive structures being substantially resonant at said predetermined operating frequency and coupled electrically to said path at coupling regions in said path which are spaced apart along said path for reflecting low impedances to said first region at the operating frequency of said apparatus.