Material in the temperature of the microwave field changes in the factors
    Materials in the microwave field temperature changes , in addition to the nature of the outside and microwave . Mainly depends on the nature of the material itself . If the material is of a different nature and humidity changes are different, that is to say , even in the same ore in the microwave field , its various minerals will have different temperature changes , the selective heating of the microwave , the temperature will result between minerals poor.
    For certain media or processing of materials, dielectric absorption power and power is proportional to the frequency and field strength . In order to improve the absorption capacity of the power , the electric field strength can be increased or increase the operating frequency . However, the electric field strength is improved with a certain extent , because the electric field strength is too high , breakdown will occur between the electrodes . And increase the operating frequency to the microwave phase , can be a good solution to this - the breakdown problem ,
    For different media , in general, the processing of the material moisture content , the greater the dielectric loss is greater. Some increase in the temperature of the material , but decreased dielectric loss , this time , there will be a so-called automatic balancing ; microwave heating effect of such a self-balancing more uniform heating of the material , but also to avoid overheating defects. However, some of the material upon heating , the dielectric constant and dielectric loss factor which increases with increasing temperature , then it will be a vicious cycle . Therefore , in the processing of a - materials, not from simply increasing microwave power or increase the frequency of its role to get shorter and shorter duration of action , but according to the nature of the materials and processing technology to the selected power characteristics , frequency and best of the shortest duration of action .
    Morphology of microwave heating substances also have a great impact. Pulverized material , because it contains a large air gap , so the relative dielectric constant and dielectric loss than the density of the compacted material through small . When water freezes below 0 ° , ice permittivity is 3.2. Dielectric loss of 0.001 , the dielectric constant of water is 80 , the dielectric loss of about 0.2 ( at 2450Hz ), the so heated frozen items, if not timely discharge of the melt water to go , since the water medium dielectric constant and dielectric loss is much greater than the ice , eventually could lead to major heat absorbed by water . While not heating the ice . This - the phenomenon described , although the same material elements , due to their different state or impurity content is not the same , may cause changes in the microwave heating .
    Should be noted that while the microwave frequency is higher, the higher the temperature , but the frequency is higher then the wave length , the smaller penetration depth . Granularity of the material , not simply the pursuit of a more high-frequency microwave string . Meanwhile, the state radio signal to strengthen management, currently only allows the use of 915MHz and 2450MHz frequencies as microwave heating equipment , higher c, K -band device available yet .