Absolute calibration of a wideband antenna and spectrometer for accurate sky noise temperature measurements
Absolute calibration of a wideband antenna and spectrometer for accurate sky noise temperature measurements
复制标题
宽带天线和光谱仪的绝对校准，用于精确的天噪声温度测量
DOI：
10.1029/2011rs004962
复制
发表时间：
2012
期刊：
影响因子：
1.6
通讯作者：
J. Bowman
中科院分区：
文献类型：
--
作者：
A. Rogers;J. Bowman
描述了一种新的绝对校准天空噪声温度的方法，该方法使用三位置开关光谱仪，使用矢量网络分析仪测量天线和低噪声放大器阻抗，以及辅助测量放大器噪声波，并与其他校准方法进行了比较。利用缅因州西福克斯55 ~ 110 MHz的观测资料对该方法进行了初步试验，以估计天空噪声谱指数。估计的精度，最终可能达到的观测，以检测或设置在无线电安静站点的红移21厘米线的限制。结论是，天线反射系数需要优于约-20 dB，以避免受到使用矢量网络分析仪的天线反射系数测量精度的限制。
A new method of absolute calibration of sky noise temperature using a three‐position switched spectrometer, measurements of antenna and low noise amplifier impedance with a vector network analyzer, and ancillary measurements of the amplifier noise waves is described and compared with other methods of calibration. An initial test of the method has been made using brief observations from 55 to 110 MHz at West Forks, Maine, to estimate the sky noise spectral index. Estimates are made of the accuracy that might ultimately be achieved with observations to detect or set limits on the red‐shifted 21 cm line at a radio quiet site. It is concluded that an antenna reflection coefficient better than about −20 dB is required to avoid being limited by the accuracy of the antenna reflection coefficient measurements using a vector network analyzer.