VHF/UHF波段树干超宽带散射特性研究

FDTD Modeling of Tree-Trunk Scattering at VHF/UHF

本文用时域方法研究了树干的超宽带散射特性 .由于树干及地面均为色散有耗媒质 ,因此树干散射特性是复杂的频率函数 .时域有限差分算法 (FDTD)尤其适合于此类具有色散特性的超宽带散射特性研究 .运用FDTD算法建立起树干散射模型后 ,经过计算 ,可以得到整个时域过程的散射 ,对时域散射场进行快速傅立叶变换 (FFT) ,则可获取全部感兴趣的超宽带频域特性 .相对于矩量法 (MOM)而言 ,FDTD能更方便快捷地为叶簇穿透 (FOPEN)检测目标提供全面的时频信息 .

This paper presents our global approach to model Ultra Wideband (UWB) FOPEN (Foliage Penetration).In this approach,we consider plane wave scattering (in time domain) from the tree trunks above the soil.The time-domain scattering is computed via FDTD method,which is particularly well adapted to frequency-dependent soil.Then with a Fast Fourier Transform (FFT),the FDTD result is transformed to the frequency domain.Thus,we may have rich information for applicability to the FOPEN detection need.