Patent ID: 6900424

Claim:
A microwave cooking appliance comprising: a cooking chamber; a toroidal-shaped waveguide including inner and outer walls, and a bottom surface which collectively define a hollow interior portion exposed to the cooking chamber; a launching zone having opposing top, bottom and side walls that define a pathway having first and second end portions and a cross-section which is different from a cross-section of the toroidal-shaped waveguide, with said first end portion opening into the hollow interior portion; a magnetron including an antenna for emitting a microwave energy field directed into the cooking chamber through the waveguide, said magnetron being mounted at the second end portion of the launching zone with said antenna extending into the launching zone, wherein the microwave energy field is directed into the launching zone, through the waveguide and into the cooking chamber; and a waveguide cover disposed between the cooking chamber and the bottom surface of the waveguide, said waveguide cover constituting a metallic conductor cover, wherein the waveguide cover shields the hollow interior portion from cooking byproducts generated in the cooking chamber during a cooking process.