有源微波冷噪声源的原理及其应用分析

Analysis of Active Microwave Cold Noise Source:Principles,and Applications

有源微波冷噪声源是一种新型微波噪声源部件,其以场效应管作为核心噪声发生元件,能够在常温环境下输出极低的噪声温度,是为微波辐射计提供低温定标参考点的理想装置。在介绍国内外有源微波冷噪声源技术发展现状和特点的基础上,分析了有源微波冷噪声源的工作原理和关键技术。提出了一种有源微波冷噪声源设计方法,重点分析了设计过程中的关键环节对噪声源性能产生的影响。采用pHEMT型场效应管研制了L波段有源微波冷噪声源器件,并给出了有源微波冷噪声源作为微波辐射计噪声源的应用方案。

A new type of microwave noise source is introduced,which is called active cold noise source.Noise wave theory is used to predict the microwave noise temperature that exits port one of a two-port active device when port two is terminated with a matched load of known temperature.This noise temperature is of interest when characterizing and designing field-effect transistor（FET）-based cold noise sources.A design procedure capable of achieving a minimum noise temperature at a specific bias point is described.An active cold noise source using pHEMT has been realized at L-band for radiometer calibration.The application of active cold noise source is discussed,and an instance that using active cold noise source as radiometer calibration reference standard is presented.