Microwave heating oven having seal means for preventing the leakage of microwave energy

In a microwave heating oven comprising a body formed by walls and having an opening in one of said walls;

• a door provided for closing said opening;
• said body and said door in a closed position defining a path through which microwave energy may leak from the inside to the outside of said oven;
• and leakage prevention means comprising a layer of microwave absorber located directly along one surface defining said path, the layer of microwave absorber incompletely blocking the opening of said path and having a surface exposed to said path, whereby said surface of said microwave absorber and opposed surface of said path form a gap therebetween, said microwave absorber consisting of a mixture of the powder of magnetic material and an organic high molecular weight compound, the improvement wherein the length of the microwave absorber along the direction of propagation of microwave in the path of microwave leakage is an integral multiple of about 1/2.lambda., wherein .lambda. is a wavelength of the microwave in the microwave absorber.