近年來，雷達都卜勒效應在軍事及民用方面的作用日益漸增，雷達都卜勒效應分析可以很好地估計目標的運動參數，如：運動方向，運動速度等訊息。而微都卜勒效應是近年來國外學者Victor C. Chen提出的一個較新的理論體系，它是建立在物體微運動模型基礎上發展起來的。 人體或其他生命體按照一定的速度、步幅和步頻走動或跑動，因此其頻譜圖呈現出微都卜勒特性。人體步態檢測及特徵提取主要是利用人體行走的動態特性對雷達回波信號進行相位調變，透過時頻分析法分析人體步態的微都卜勒特徵及參數提取。 穿牆探測是指透過牆體或其他障礙物後的探測技術。並且廣泛應用於生物醫療、安全檢測和反恐等方面，同時也對今後進一步研究和實現人體目標分類、各種不同狀態分析等提供了一定基礎。 本文首先根據點目標的典型微運動模型：振動和旋轉，討論了在振動和旋轉模型下的微都卜勒效應。接著介紹時頻分析工具，並建立了人體步態回波模型，呈現了各關節、散射部位和散射部位上的瞬間雷達截面積(RCS)之間的相對旋轉角度、位移及相位關係，最終結合穿牆探測，試驗人體步態行進方向判別在穿牆下的可行性。 ;Radar Doppler has various applications in both military and civil aspect. The target moving parameters such as moving direction, moving velocity and so on can be well estimated through the analysis of radar Doppler effects. A new research called micro-Doppler which is proposed by the famous scholar Victor C. Chen was developed on the basis of micro motion model of objects. Since the human beings and the other creatures usually walk or run with a constant velocity, stride and gait frequency, there are some micro-Doppler signatures on their spectrums. Human gait detection and characteristic extraction mainly utilize the human’s walking dynamic features to modulate the radar echo phase, use time-frequency analysis method to obtain the spectrum, and extract the micro-Doppler signature of human gait from spectrum. Through wall surveillance (TWS) is a kind of detection technology which can penetrate walls and other obstacles. With the ability of through-obstacle detection, TWS has been playing an important role in military reconnaissance, counter-terrorism, hostage rescue, earthquake casualty search and so on. In this study, the micro-Doppler effect of the vibration and rotation is firstly discussed which is depend on the specific micro motion, and followed by the tool of time-frequency analysis. A gait echo model is proposed, which represents the rotation angles, displacements and relative phase relationship of joints, scatterers and the instantaneous Radar Cross Section (RCS). Finally, micro Doppler is combined with TWS for the feasibility of human gait direction determination.