基于微波反射率波动特性的混凝土介电常数测量方法  

Measurement method of concrete permittivity based on microwave reflection interference

作　　者：刘君[1] 许卫东[1] 刘珩[1] 渠立永[1] 马瑶[1] 

机构地区：[1]解放军理工大学野战工程学院,江苏南京210007

出　　处：《电波科学学报》2015年第1期141-146,共6页Chinese Journal of Radio Science

基　　金：重点实验室基金(No.FD2013007)

摘　　要：提出了通过自由空间一次线性扫频测量混凝土背贴金属板时的表面反射率,分析反射率随频率的周期波动间隔,快速获得介电常数的测量方法.经测量和比较不同厚度、背贴金属板或吸波材料两种状态的混凝土表面微波反射率,验证了试件表面和底面反射波的相互干涉是反射率随频率周期波动现象的主要原因.根据波动干涉原理,给出了由试件厚度、微波入射角度和反射率极值频率间隔,计算混凝土介电常数的公式.由于计算过程不需要反射率的具体数值,测量影响因素少,易于得到介电常数准确值,且操作简便、计算快速.A new rapid permittivity measuring method is given through once frequency sweep to obtain the free space reflectivity of concrete plate backed with metal plate.The permittivity is calculated from the reflectivity fluctuating repetition in frequency domain.The interference between surface and bottom reflection is the main cause of microwave reflection fluctuating,which was verified with reflectivity measurement under different condition such as different concrete plate depth,backed on metal plate or absorbing material.According to wave interference theory,the permittivity was calculated from material depth,incidence angle and frequency interval,the result coincides with reference literature well.As the exact reflectivity is not a necessary computing parameter,the error caused by echo clutter is minimized,the exact permittivity can be obtained conveniently from once frequency sweep measurement.

关 键 词：自由空间法 微波反射率 混凝土 介电常数 

分 类 号：TU528[建筑科学—建筑技术科学]