Electromagnetic wave energy seal arrangement

Claim 1

In a microwave oven including a source of microwave energy with a predetermined frequency, a heating cavity for receiving items to be heated by the microwave energy and having an access opening, a door for opening and closing the access opening, and a door seal arrangement for preventing the leakage of microwave energy through a door gap, said door seal arrangement of a microwave oven comprising: a recessed chamber having a choke function, said recessed chamber being defined substantially rectangular configuration by an internal plate member and an external plate member, the length of said recessed chamber being substantially λ/4 of the effective wavelength for minimizing the leakage path of the microwave energy in the longitudinal direction, a stepped portion formed by said internal plate member, said stepped portion having upper and lower horizontal portions, a vertical portion, and first and second capacitive seals for changing its capacitance by said stepped portion, whereby the propagation path makes a characteristic impedance different from each other, a plurality of slots formed at said lower horizontal portion and said vertical portion of said internal plate member, said plurality of slots being formed at predetermined periodical intervals, whereby a band stopping filter is gained for suppressing the microwave energy proceeding to the x-direction, a C-shaped member disposed at the bottom end portion of said external plate member for forming the second capacitive seal between a front panel of said heating cavity, and a choke cover for blocking an opening of said recessed chamber, said choke cover being located between said C-shaped member and said lower horizontal portion of said stepped portion.