We report on the measurements of the complex refractive index of a number of low-loss polymers using a quasi-optical vector network analyzer operating in the frequency range of 210–370 GHz. The process of extracting both the real and imaginary parts of the refractive indexes is presented in this article, along with the method of error estimation. The measured refractive indexes of 25 different material samples, as well as the estimated error and the loss tangents of thicker samples, are tabulated. For selected materials, loss tangents have also been confirmed using the method of intersecting lines, which measures the additional input noise to a superconductor–insulator–superconductor receiver due to the dielectric sample. The data obtained from this work will be useful for the design of low-loss vacuum windows for cryogenic receivers operating in the 300-GHz range.

中文翻译：

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用于真空 Windows 应用的 300 GHz 低损耗聚合物的准光学表征

我们报告了使用在 210-370 GHz 频率范围内工作的准光学矢量网络分析仪测量多种低损耗聚合物的复折射率。本文介绍了提取折射率的实部和虚部的过程以及误差估计方法。表中列出了 25 种不同材料样品的测量折射率，以及较厚样品的估计误差和损耗角正切。对于选定的材料，损耗正切也已使用相交线的方法得到确认，该方法测量由于介电样品而导致的超导体-绝缘体-超导体接收器的额外输入噪声。