In microwave heating applications, the energy is introduced directly into the volume of the material and as consequence the quality of the process is highly dependent on the uniformity of the electromagnetic field distribution along it. That is, the non uniformity of the heating is a potential problem with serious consequences. Thermal runaway is the most critical, in materials with temperature dependent dielectric properties. As the material absorbs electromagnetic energy, the temperature increases as does its ability to absorb more energy.
To understand this phenomenon, a perceptive of how electromagnetic field propagates and how is absorbed by materials is essential, and then, we carried out the 3D electromagnetic field simulation in a microwave oven loaded with a ceramic sample, changing several parameters, as the dielectric properties of the load and the magnetron frequency, using COMSOL software.