Microwave heating method and apparatus including adjustable tuning members

摘要

A method and apparatus for matching a microwave heater to reduce the microwave energy reflected by the load, wherein microwave energy from a microwave energy source is supplied to a treatment chamber by a hollow waveguide of rectangular section. A directional coupler in the waveguide prevents reflected energy returning to the source and directs it to absorption means. A detector is provided at the absorption means to measure the reflected energy and produce a signal, and control means is provided to operate control motors to operate tuning pins provided in the waveguide, the control motors having different operating speeds.