标题： 准光学、校准过的220-330 GHz频段真空低温器件全2端口测量 显示英文标题

标题： Quasioptic, Calibrated, Full 2-port Measurements of Cryogenic Devices under Vacuum in the 220-330 GHz Band

摘要： 设计、仿真和校准了一个准光学（QO）测试平台，用于表征220-330 GHz（WR-3.4）频率范围内的器件的S参数，温度从室温降至4.8 K。这些器件通过聚焦束辐射透过真空窗进行测量。 建立了一种采用线-反射-匹配（LRM）校准方法的去嵌入技术，以考虑光学组件和真空窗的影响。 该装置提供所有四个S参数，参考平面位于低温恒温器内部，并且在空载夹具的情况下实现了30 dB的回波损耗。 系统验证通过低温冷却器件（如裸硅晶圆、不锈钢频率选择表面（FSS）带通滤波器以及铌制超导带通FSS）的测量完成。 观察到基于4 GHz谐振位移的硅介电常数随温度从296 K降至4.8 K而降低。不锈钢FSS的测量结果显示中心频率和回波损耗分别为263 GHz和35 dB，相对温度变化不大。 最后，使用超导滤波器测得中心频率为257 GHz，在4.8 K时平均回波损耗提高了7 dB。据我们所知，这是首次尝试将LRM校准扩展到330 GHz，并利用它来去嵌光学和低温恒温器对低温冷却器件S参数的影响。 显示英文摘要

摘要： A quasi-optical (QO) test bench was designed, simulated, and calibrated for characterizing S-parameters of devices in the 220-330 GHz (WR-3.4) frequency range, from room temperature down to 4.8 K. The devices were measured through vacuum windows via focused beam radiation. A de-embedding method employing line-reflect-match (LRM) calibration was established to account for the effects of optical components and vacuum windows. The setup provides all four S-parameters with the reference plane located inside the cryostat, and achieves a return loss of 30 dB with an empty holder. System validation was performed with measurements of cryogenically cooled devices, such as bare silicon wafers and stainless-steel frequency-selective surface (FSS) bandpass filters, and superconducting bandpass FSS fabricated in niobium. A permittivity reduction of Si based on 4-GHz resonance shift was observed concomitant with a drop in temperature from 296 K to 4.8 K. The stainless steel FSS measurements revealed a relatively temperature invariant center frequency and return loss level of 263 GHz and 35 dB on average, respectively. Finally, a center frequency of 257 GHz was measured with the superconducting filters, with return loss improved by 7 dB on average at 4.8 K. To the best of our knowledge, this is the first reported attempt to scale LRM calibration to 330 GHz and use it to de-embed the impact of optics and cryostat from cryogenically cooled device S-parameters.