Modeling microwave propagation in a grass vegetation layer

A formulation is presented for evaluating the complex propagation constant describing a coherent electromagnetic wave propagating in a grass vegetation layer. This problem differs from that of many other vegetation media, in that the size of the constituent elements are of the same size as the vegetation layer. The key assumption in the formulation is that the diameters of the long, thin grass elements are electrically small, and thus can be considered electromagnetically as line-dipole structures. It is shown then that for a random media, consisting of line-dipole elements, the propagation can accurately be represented through an incremental layer of vegetation. However, the extinction due to scattering is underestimated using this Rayleigh formulation. Therefore, the scattering solution for a general line-dipole element was used to evaluate its extinction due to scattering, and this result was then used to modify the polarizability tensor expression in order to account for losses due to scattering