Heating performance of microwave ovens powered by magnetron and solid-state generators

Magnetrons are the most common microwave power sources. However, variation of output frequencies of magnetrons makes heating patterns of foods in multi-mode microwave cavities random and unpredictable. It is desirable to find effective alternatives, such as solid-state microwave generators. Here, we compared the frequency spectra of magnetrons and solid-state generators to evaluate their influence on the heating performance of microwave ovens. Results showed that the spectrum (i.e., peak frequency and bandwidth) of microwaves from the magnetron varied depending on the food and food position and varied considerably between individual ovens of the same model. In contrast, the solid-state microwave generator provided microwaves not only at exactly the set frequency but also within a narrow band, regardless of food loads. That is, solid-state generators had better spectral quality than that from magnetrons. As a result, solid-state generators would provide predictable and stable heating patterns of foods that cannot be achieved with magnetrons. Therefore, solid-state generators create new opportunities in designing next-generation microwave systems with high heating performance.