分形土壤面与上方复杂目标复合电磁散射的MOM研究

Study on Composite Electromagnetic Scattering from the Fractal Soil Surface and the Complex Target above It by Using Method of Moments

基于复合散射研究在实际应用中的价值,实际的沙壤土面采用一维带限Weierstrass分形模型模拟,用导弹模型作为其上方目标,在TM波入射时,运用矩量法分别讨论土壤面的高度起伏均方根(δ)、湿度(mv)、分维数(D),目标的横纵向尺寸(l、d)与目标的高度(H)及入射波的频率(f)对复合散射特性的影响,通过数值计算得到每种情况对应的复合电磁散射系数(σ)的散射角(θs)分布.结果表明:对σ有明显影响的因素有δ、mv、H以及f,而对其影响较小的因素有D、l、d.

Based on the value of the practical application about the composite scattering research the actual sandy loam surface is simulated with model of 1D band-limited fractal function and the missile model is adopted as its top target. When the TM wave incidences,the influences of the root mean square,the surface moisture,the fractal dimension of the soil surface,the transverse size and the longitudinal dimension,the height of the target and the frequency of the incident wave on the composite scattering characteristics are analyzed respectively with the method of moments. The varying curves of electromagnetic scattering coefficients with the scattering angles are obtained by numerical calculation. The results show that the influences of the soil root mean square,the soil surface moisture, the height of the target,and the frequency of the incident wave on composite electromagnetic scattering coefficients are obvious,while the influences of the fractal dimension of the soil surface,the transverse size of the target,the longitudinal dimension of the target are not obvious.