基于共面波导传输线的宽频带介电常数提取方法

Broadband Dielectric Constant Extraction Method Based on Coplanar Waveguide Transmission Line

提出了一种基于共面波导传输线的宽频带低损耗材料介电常数提取方法。设计5根共面波导传输线作为标准覆盖待测样品介电常数频率范围,采用在片矢量网络分析仪测得各传输线未经修正的S参数,经过多线TRL校准算法提取传播常数;采用quasi-TEM模型计算传输线的单位长度电阻R和单位长度电感L;最终求得0.1~50 GHz GaAs材料的介电常数。相比于传统的腔体法只能点频测试,且需设计待测样品腔体结构,该测试方法支持宽频带介电常数的连续测试,且测试效率更高;测试结果与谐振腔法偏差±2.5%,满足工程实践需要。

A broadband method of extracting dielectric constant of low-loss materials based on coplanar waveguide transmission line is introduced. Fabricated five transmission lines as test sample and measured the raw data by vector network analyzer. After calculating the propagation constant from measurements of five line lengths based on multiline TRL apply an analytic CPW model to extract the broadband dielectric material properties of the substrate material GaAs from 0.1 GHz to 50 GHz.Contrast to conventional resonator measurement method with single frequency test and complex construct, the proposed method can make continuous broadband test with more efficient. The results show excellent agreement between these two methods, the difference is within ±2.5%, and meet the need of engineering design.