介电薄膜的相对介电常数是介电材料的重要表征参数之一.在表征未知材料之前,需要用已知材料——二氧化硅验证表征方法的准确性.针对这一问题,提取了两组不同长度硅基共面波导型传输线的S参数,基于保角映射原理,使用三种不同的方法,先得到器件的有效介电常数以及结构参数,然后表征得到介电薄膜的相对介电常数.结果表明:S21表征法的平均偏差约1.435％,单线表征法的平均偏差约为0.483％,双线表征法的平均偏差约为0.448％.因此,可以得出结论:三种方法均可以准确地表征相对介电常数.%The relative permittivity of dielectric thin film is one of the most important characterization parameters.It's necessary to verify the accuracy of characterization by known material,usually silicon dioxide,before characterizing the unknown material.Two groups of experimental S-parameter dates with different lengths for silicon-based coplanar waveguide transmission lines were extracted.Three different characterization methods based on conformal mapping were used.At first,the effective dielectric constant of the device and the structure parameters were get,and then,precisely characterize the relative permittivity of dielectric thin film.The result shows that the average deviations of the S21 method,single-line method and double-line method are about 1.435％,0.483％ and 0.448％.Thus,the conclusion can be made that the characterization is accurate enough by these three methods.
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