圆柱腔径向双层介质厚度的测量方法  

Measurement Method of Radial Double-Layer Dielectric Thickness of Cylindrical Cavity

作　　者：张淑娥[1,2,3] 赖帅 张京席 ZHANG Shue;LAI Shuai;ZAHNG Jingxi(Department of Electronic and Communication Engineering,North China Electric Power University,Baoding 071003,Hebei,China;Hebei Key Laboratory of Power Internet of Things Technology,North China Electric Power University,Baoding 071003,Hebei,China;Baoding Key Laboratory of Optical Fiber Sensing and Optical Communication Technology,North China Electric Power University,Baoding 071003,Hebei,China)

机构地区：[1]华北电力大学电子与通信工程系,河北保定071003 [2]华北电力大学河北省电力物联网技术重点实验室,河北保定071003 [3]华北电力大学保定市光纤传感与光通信技术重点实验室,河北保定071003

出　　处：《华南理工大学学报（自然科学版）》2022年第10期87-93,共7页Journal of South China University of Technology(Natural Science Edition)

基　　金：河北省自然科学基金资助项目(E2019502039)。

摘　　要：蒸汽湿度的精确测量对维护汽轮机的稳定性有重大意义,而蒸汽湿度的测量又受水膜厚度的影响。为了解决圆柱腔内壁水膜厚度的测量问题,基于介质加载圆柱谐振腔内谐振频率随介质厚度变化的原理,提出一种用于测量圆柱腔内壁介质厚度的新方法。根据介质加载圆柱波导所满足的麦克斯韦方程组和边界条件,推导了填充双层介质圆柱波导的特征方程。在给定介质厚度的情况下,根据特征方程给出了传播模式的相位常数和波导工作频率间的关系;基于推导的特征方程,建立了圆柱腔内壁介质厚度和谐振频率值之间的关系模型。应用MATLAB软件进行数值求解,得到不同介质、不同厚度下对应的谐振频率。在与数值求解设定的同等参数下,利用HFSS软件仿真分析了双层介质加载圆柱腔对应的谐振频率。将仿真数据和理论计算数据进行对比,结果表明随着介质厚度的增加,两者都呈平行下降趋势,且谐振频率频偏与介质厚度呈线性关系的规律,验证了该方法的可行性。该方法测量的介质厚度没有限制(在半径以内),具有普适性。文中还利用网络分析仪进行了相关实验,并搭建了实用性测量系统,当介质厚度在100μm以内时,每间隔10μm所能测得的介质厚度值的间隔约为6.8~7.1μm,相对测量误差不超过24.6%。通过理论数据与实验数据对比,发现该方法测出的数据更为精确。Accurate measurement of steam humidity is of great significance for maintaining the stability of steam turbine.The measurement of steam humidity is affected by the thickness of the water film.To solve the problem of measuring the thickness of water film on the inner wall of cylindrical cavity,this paper proposed a new method for measuring the thickness of dielectric film on the inner wall of cylindrical cavity based on the principle that the resonant frequency of a dielectric loaded cylindrical cavity varies with the thickness of dielectric film.The characteristic equation of cylindrical waveguide filled with double-layer dielectric was derived according to Maxwell’s equations and boundary conditions of dielectric loaded cylindrical waveguide.Under the given dielectric film thickness,the relationship between the phase constant of propagation mode and the working frequency of waveguide was given according to the characteristic equation.Based on the derived characteristic equation,the study established the model of relationship between the thickness of dielectric film on the inner wall of cylindrical cavity and the value of resonance frequency.The resonant frequencies corresponding to different media and different thicknesses were obtained by numerical solution with MATLAB software.Under the same parameters as those set by numerical solution,the resonant frequencies corresponding to the cylindrical cavity loaded with double-layer media were simulated and analyzed by HFSS software.Comparing the simulation data with the theoretical calculation data,the results show that with the increase of the dielectric film thickness,both of them show a parallel downward trend,and the resonance frequency offset is linearly related to the dielectric film thickness,which verifies the feasibility of this method.There is no limit to the thickness of dielectric film measured by this method(within radius),and this method is universal.A network analyzer was used to carry out related experiments,and a practical measurement system was bu

关 键 词：圆柱波导 径向双层介质 特征方程 介质厚度 网络分析仪 测量系统 

分 类 号：TN015[电子电信—物理电子学]