中文摘要：

关于信杂比及杂波谱的研究对于杂波背景下目标的检测具有重要的指导意义，然而窄带雷达已有的相关理论在超宽带雷达中已经不再适用，需重新进行研究。本文以机载雷达为背景，全面地分析超宽带条件下信杂比及杂波谱的变化，并给出仿真结果。

英文摘要：

It is very important to study the signal to clutter ratio （SCR） and the power spectral density （PSD） of the clutter as a basis for studying the target detection in the background of clutters. However, the relevant theory used in the narrow-band radar can not be applied directly in the ultra-wide-band （UWB） radar so a new theoretical system for UWB radar needs to be established. The preliminary work is study of SCR and the clutter＇s PSD. In this paper, the change of the SCR and clutter＇s PSD in UWB radar is analyzed comprehensively and the relevant formulae are derived. A simulation experiment is performed, which shows that the SCR will be increased and the main lobe of the clutter＇s PSD will be broadened with the increasing of the transmitted signal＇s fractional bandwidth.