Patent ID: 7227109
Filing Date: 2007-06-05
Classification: H05B,Y02B

Abstract:
1. A microwave oven having wall means defining an oven cavity to receive food to be cooked, the wall means having a launch wall with an aperture therein; a launch box mounted on the external side of the launch wall so as to cover the aperture; three sides of the box being in respective communication with three waveguides each fed by a respective magnetron so that there are three magnetrons all operative to supply microwave energy through the common launch box and the common aperture and thence into the oven cavity, wherein the launch box is of cuboid shape to three side walls of which are respectively fitted the three waveguides respectively fed by the three magnetrons, wherein the launch box has two opposite side walls and in intermediate side wall, and in which two of the three waveguides are attached to opposite side walls of the box and have a longer length than the third waveguide which is attached to the intermediate wall of the box, and wherein the pair of longer waveguides each have an effective length corresponding to one wavelength at the operating frequency of the corresponding magnetron and the shorter waveguide has an effective length corresponding to one half wavelength at the corresponding frequency.