对于空间技术和天文观测中应用的1～5μm大气窗口的高灵敏红外探测系统,前置放大器已经开始成为限制灵敏度的重要因素。对前置放大器的要求,除了尽可能低的噪声外,其频率响应及动态范围也应满足一定的要求。为了改善引线电容对频率特性的影响,同时也减小低温下引线的微音效应,前置放大器的输入级尽可能靠近工作于低温下的探测器是必要的。因此,研究结型场效应管(JFET) Preamplifiers have begun to become an important limiting factor for high sensitivity infrared detection systems with 1 to 5 μm atmospheric windows used in space technology and astronomical observations. The preamplifier requirements, in addition to the lowest possible noise, the frequency response and dynamic range should also meet certain requirements. In order to improve the effect of lead capacitance on the frequency characteristics and also to reduce the whispering effects of the leads at low temperatures, it is necessary that the preamplifier’s input stage be as close as possible to the detector operating at low temperatures. Therefore, the study of junction FET (JFET)