A fundamental study of microwave liquid heater

As a heating system utilizing microwave energy, microwave ovens using magnetron are widely used for some reasons such as cooking promptness, high efficiency, handiness, and adjustment, etc. Microwave ovens, however, lack versatility because of heating in a closed space. In this paper, we propose a heating unit composed of rectangular waveguide with many holes much smaller than the wavelength in the waveguide to develop a novel microwave liquid heating system in an open space. Furthermore, size-reduction of the heating unit is realized by using a heat-resisting glass as a matching element. Temperature elevation up to over 180 degrees C of a cooking oil is also confirmed by experiment.