Efficient Method for Scattering From Cylindrical Components of Vegetation and Its Potential Application to the Determination of Effective Permittivity

Reliable and efficient analysis of electromagnetic scattering by cylindrical components of vegetation is important for microwave remote sensing of vegetated terrain. It allows for the characterization of anistropicity of the effective permittivity for vegetation or tree canopy, where averaging operation over distribution of cylinder orientation is needed in general. In this paper, we propose a T-matrix formulation based on our virtual partition method (VPM) for the whole cylindric component of either homogeneous or inhomogeneous nature. Numerical simulations demonstrate that the proposed T-matrix preserves all the desirable features of the VPM method, including high fidelity prediction of the scattering amplitude function and fulfillment of energy conservation as well as the reciprocity theorem. More importantly, in the evaluation of averaging over orientation distribution, the proposed method is usually faster than the VPM by two orders of magnitude. The predicted effective permittivity for an exemplary orientation distribution shows appreciable difference from that of the infinite cylinder approximation. With its qualitatively characterized region of validity, the proposed method is expected to be helpful in multiband coherent scattering models of vegetated terrain.