Feedback control procedure for energy efficiency optimization of microwave-heating ovens

This paper presents an automatic calibration procedure that permits to industrial or domestic microwaves ovens working at optimal energetic efficiency conditions. This method is based on a low-power iterative measurement of the microwave oven scattering parameters for several sample locations to find the most efficient position by measuring energy reflections at feeding ports and the coupling between them for each sample position. These low-power measurements have been validated through high-power microwave-heating tests showing that, at the optimal estimated position, microwave absorption and therefore temperature increment is maximum. The method provides good matching levels independently of the sample geometry and permittivity without the need of any external matching device.