Control of Microwave Heating in Rectangular Waveguide and Rectangular Cavity

微波加热具有电磁波的透射、吸收和反射的特征。材料中的透射波和反射波的相互干涉是影响加热效果的重要因素。利用频率为2.45GHz的TE模微波<10>，在矩形波导和矩形腔中，研究了反射板和入射波控制板对微波加热特性的两种影响。（1）在没有反射板的正常情况下，发热量在谐振状态处具有峰值，对应于样品半波长的整数倍。当反射板安装在最佳位置时，发热量增加。然而，随着样品长度变得更长，由于微波的阻尼，反射板的效果变得更小。(2)为了避免样品表面的反射，可以在样品上附着低介电材料。通过附接具有最佳相对介电常数并且厚度为四分之一波长的波控制板，与正常加热相比，发热量增加。(3)为了阐明矩形波导中微波加热的优化问题，提出了在样品上附加反射板和入射波控制板的两种方法，并指出了通过控制反射波和透射波来优化微波加热的指导思想。(4)对于矩形腔体中的微波加热，同样提出了在样品上附加反射板和入射波控制板的两种方法，并指出了通过控制反射波和透射波来优化微波加热的指导思想。

Microwave heating has the features in a transmission, absorption and reflection of an electromagnetic wave. The performance of the heating strongly depends on the interference of the transmitted wave and reflected wave in materials. Using the microwave of TE_<10> mode and frequency of 2.45GHz in a rectangular waveguide and a rectangular cavity, we have investigated two effects of a reflecting plate and an incident wave control plate on the characteristics of microwave heating.The results obtained here are summarized as follows ;(1) In the normal case without the reflecting plate, the quantity of heat generation has peaks at the resonance states, corresponding to the integer multiple of half wavelength of the sample. The quantity of heat generation increases when a reflecting plate is installed in the best position. However, as the sample length becomes longer, the effect of a reflecting plate becomes smaller because of a damping of microwave.(2) In order to avoid the reflection on the surface of the sample, it is available to attach a low dielectric material on the sample. By attaching the wave control plate having the optimum relative permittivity and having a quarter wavelength in thickness, the quantity of heat generation increases, comparing with the normal heating.(3) In order to clarify the optimization of microwave heating in a rectangular waveguide, we proposed two procedures attaching a reflecting plate and an incident wave control plate to the sample and indicated the guideline for the optimization of microwave heating by controlling reflected and transmitted waves.(4) For microwave heating in a rectangular cavity, we similarly proposed two procedures attaching a reflecting plate and an incident wave control plate to the sample and indicated the guideline for the optimization of microwave heating by controlling reflected and transmitted waves.