MICROWAVE HEATING APPARATUS WITH FUNDAMENTAL AND SECOND HIGHER HARMONIC CHOKES

摘要

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.