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本文概述低温噪声源的原理、国内外情况及其应用。文章重点介绍了不用低温噪声源对微波辐射计进行直接与间接定标的原理、方法,以及Ka波段和χ波段“冷源”研制过程中所需解决的波导绝热,低温密封与防止凝霜、温度分布测试、小衰减精密测量以及标定低温噪声源输出噪声温度和它的精度等技术关键。文章最后给出了“冷热源”对三厘米和八毫米辐射计定标的试验数据,评价了低温噪声源定标辐射计的实际效果。
This article outlines the principle of low temperature noise sources, the situation at home and abroad and its application. In this paper, the principles and methods of direct and indirect calibration of microwave radiometers without cryogenic noise sources are introduced. The waveguides, which are required to be solved during the development of Ka-band and χ-band “cold source” Temperature distribution test, small attenuation precision measurement and calibration of low temperature noise source output noise temperature and its accuracy and other technical key. At the end of the article, experimental data of “cold and heat source” on the calibration of three and eight millimeter radiometers are given, and the actual effect of low temperature noise source calibration radiometer is evaluated.