摘要 : A system to measure the noise temperature (NT) of noise sources is implemented in the frequency range of 18–26.5 GHz for the case where noise sources commercially available have only one nominal NT, e.g., 9500 K being equivalent t... 展开 A system to measure the noise temperature (NT) of noise sources is implemented in the frequency range of 18–26.5 GHz for the case where noise sources commercially available have only one nominal NT, e.g., 9500 K being equivalent to 15-dB excess noise ratio. For the Y-factor method, two noise sources, i.e., a noise source and another with a radio-frequency attenuator, serve as the standard noise sources. The noise power output of the noise sources are measured using a commercial noise figure measurement instrument. Measurement results are presented, and its uncertainty has been evaluated to be 0.23–0.25 dB $(k = 2)$ . 收起