Abstract: A microwave heating apparatus having a door equipped with a microwave attenuating cavity constituted by a fundamental wave choke channel and a second higher harmonic choke channel opposing thereto back to back. A wall surface defining the second higher harmonic choke channel has a periodic structure provided with a plurality of trapezoidal metal pieces a tip of each of which is bent inwards. The periodic structure efficiently guides leakage microwave energy into the microwave attenuating cavity and promotes microwave energy leakage preventive effect. The door is suitable for reduction in size and thickness and permits a microwave heating apparatus of improved space factor to be provided.

Abstract: A microwave oven having special form of a microwave energy radiation arrangement.In order to heat uniformly materials to be cooked, the microwave energy radiation arrangement includes a rotatable conductive rod extending into an oven chamber through a hole located substantially in the center of one oven chamber wall, a rotating conductive arm having one end fixed on the rod so as to extend transversely thereto, and a conductive plate having the center thereof coincident with the axis of the rod and arrayed such that the rotating arm is interposed between the one wall and the conductive plate. Openings for radiating microwave energy into the oven chamber are formed at the periphery of the conductive plate.