Heating pattern of frozen food affected by microwave oven frequency

In this study, the frequency distributions of a commercial domestic microwave oven with and without load were measured. Computer simulation model was developed to study the influence of varying frequencies on heating pattern of frozen food while heated in a domestic microwave oven. A commercial software tool QuickWave was used to build up the simulation model using the finite-difference time-domain (FDTD) method to solve coupled electromagnetic and heat transfer equations. Results showed that the operating frequency of a domestic microwave oven was constantly changing with time. The heating patterns of stationary and rotating frozen food changed when the frequency varied from 2400 to 2500 MHz. The cold and hot spots of frozen foods were not stable even for the same load due to the shifting frequencies.