VARIABLE-IMPEDANCE UNIT, MICROWAVE DEVICE USING THE UNIT, AND MICROWAVE HEATER

摘要

A compact and highly controllable impedance-varying-unit, a microwave device using the same unit, and a high-frequency-heating appliance using the same unit are provided. The impedance varying unit includes a rectangular waveguide-section as a main body made of metallic material, an open end of waveguide-section working on microwave in a microwave cavity, a terminal end of waveguide-section closed by metallic material, a rotary movable body made of non-metallic material, and a driver for the movable body. A rotating angle or a position of the movable body is controlled, so that an impedance at the open end is varied and transmission status of microwave is changed, thereby variably controlling a standing wave distribution. Controlling the standing wave distribution allows an object in the cavity to be selectively heated or uniformly heated. Further, the standing wave produced in the microwave cavity is sequentially varied, so that the object can be selectively heated or uniformly heated. The present invention solves the problem of spark production, and provides a compact as well as highly controllable impedance varying unit, a microwave device using the same unit and a high-frequency-heating appliance using the same unit.