Microwave ovens for uniform heating

Abstract

Microwave ovens typically have an oven cavity and a feed system for supplying microwaves through a feed opening into the cavity. Such ovens are inproved by providing a field stirrer rotatably mounted over and covering the feed opening. The field stirrer is a single conductive plate having a single radiating slot in the plate exposing only a portion of the feed opening to the cavity through the slot at any position of the plate during its rotation. The slot is in the shape of an arc or other shape which is tangentially longer than it is radially wide. The plate also has a plurality of wings, fins, or vanes outside the feed opening. The vanes and slot are arranged so that electrically identical positions of the plate occur only every full circle of rotation by virtue of bilateral symmetry at most. The plate is spaced from the feed opening and into the cavity by a sufficient distance to permit flow of microwave energy beneath the plate for distribution around the periphery of the plate and by the vanes. The geometry and dimensions of the slot, plate periphery, and vanes can readily be adjusted for best cooking in actual practice. In an additional embodiment the plate periphery cooperates with the feed opening in the manner of a slot without need of slotting the plate itself.