Branches modeling in forest electromagnetic propagation and scattering at L and P bands

In usual models for forests electromagnetic scattering (see [l],[3],[4]for example), branches are often represented by straight homogeneous cylinders of finite length. According to the category of tree under consideration, this assumption may be reasonable or unduly exaggerated according to the way branches are curved or exhibit a section evolution [2]. In this case, there is the possibility of representing a long, curved branch into smaller straight ones, but the electromagnetic computation may be affected by this way of representation. The present paper treats these points numerically using Finite Differences in Time Domain ([5][6][7])for these shape effects, including curvature and thinning effects.