Generally, in the field of energy processing, most of the materials processed are dielectric materials, and the dielectric materials generally absorb microwave energy to different extents. The dielectric materials and microwave electromagnetic fields are coupled to each other, which will form various power dissipations to achieve energy conversion. There are many ways to convert energy, such as ion conduction, dipole rotation, interfacial polarization, hysteresis, piezoelectric phenomenon, electrostriction, nuclear magnetic resonance, ferromagnetic resonance, etc., where ion conduction and dipole rotation are microwaves. The main principle of heating. Microwave heating is a heating method that relies on the absorption of microwave energy by an object to convert it into heat energy and heat the whole body at the same time, which is completely different from other conventional heating methods.
The traditional heating method is to transfer heat from the outside to the heat of the material according to the principle of heat conduction, convection and radiation. The heat is always transferred from the surface and the inside to heat the material. There is inevitably a temperature gradient in the material, so the heated material is uneven, resulting in the material. Local overheating occurs; microwave heating technology is different from traditional heating method in that it generates high temperature reciprocating motion of the dipole molecules inside the heating body to generate "internal friction heat" to raise the temperature of the heated material without any heat conduction process. The material can be heated simultaneously and simultaneously at the same time, and the heating speed is fast and uniform, and only a fraction or a fraction of the energy consumption of the conventional heating method can be used for heating purposes. From the theoretical analysis, the amount of heat generated by a substance in a microwave field has a great relationship with the type of substance and its dielectric properties, that is, the characteristic that the microwave has selective heating of the substance.