Two independent methods of absolute power measurement of electromagnetic waves are compared in the millimeter-wave range. At the National Metrology Institutes (NMIs), dependent on frequency and wave propagation, electromagnetic power is differently traced back to the International System of Units (SI), i.e., from microwave up to millimeter-wave frequencies in coaxial lines and metallic waveguides and terahertz frequencies in free space. As state-of-the-art waveguide-based power sensors and free-space power detectors are overlapping with respect to their operating frequency, for the first time, a comparison of both independent power scales has been carried out in the millimeter-wave range. The experiment verified the consistency of both traceability approaches within their uncertainties.

中文翻译：

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连接自由空间和基于波导的电磁波的功率标度

在毫米波范围内比较了两种独立的电磁波绝对功率测量方法。在国家计量院 (NMI)，根据频率和波传播，电磁功率可追溯到国际单位制 (SI)，即从微波到同轴线、金属波导和太赫兹中的毫米波频率自由空间中的频率。由于最先进的基于波导的功率传感器和自由空间功率检测器在其工作频率方面存在重叠，因此首次在毫米波范围内对两个独立的功率尺度进行了比较. 实验验证了两种溯源方法在其不确定性范围内的一致性。