聚合物薄片的复介电常数微波测量方法

提出了一种在微波频域测量聚合物样品薄片复介电常数的方法,它利用自动测量线测试系统测量出电压驻波比和相角,然后采用级数各阶次展开方法,由反射系数推导出复介电常数.级数低阶次方法求解厚度较大的被测样品复介电常数时,为确保结果具有较高的精确度,要求测量频率不超过1.5GHz.为了克服这种测量频域的局限性,可采用级数高阶次展开方法来求解复介电常数.用级数展开方法测量聚苯乙烯、多乙酸乙烯酯和聚亚胺酯的复介电常数值,结果与真实值相近,可以和传输/反射法相媲美.

Measuring Complex Permittivity of Polymer Thin Sheet Using Microwave Method

A method of measuring the complex permittivity of a thin sheet of polymer sample at microwave frequency is presented.In order to obtain the complex permittivity in terms of reflection coefficient,a higher order power series solution is preseneted,and the Voltage Standing Wave Ratio(VSWR) and Phase Angle are measured by automatic slotted line system.Application of lower order power series solution to the greater thickness of the sample requires a frequency of less than 1.5 GHz.To overcome this constraint and to extend the range of working frequency,the higher order power series solution is used to obtain the complex permittivity.This method is used to measure the complex permittivity of polystyrene,polyvinyl acetate,and polyurethane.The results,being in good agreement with literature,show that the method compares well with the transmission/reflection technique.