Wave Mode and Path Characteristics in a Four-Layered Anisotropic Forest Environment

A four-layered forest geometry with two anisotropic slabs representing canopy and trunk is used for the investigation of wave characteristics in forest environment. Propagation of radio waves is examined in which the transmitter is embedded inside the forest, while the receiving point is located either inside the forest or above the vegetation. Dyadic Green's functions in their eigenfunction expansion forms for planarly layered anisotropic media are applied to analyze this problem. The analytical close forms of these electric fields are then obtained by using the saddle point techniques, and branch cut integrations in the complex plane and, hence, expressed in terms of quasidirect wave, multiply reflected waves, and lateral waves. Propagation mechanisms of these waves are studied and radio losses in a typical forest are calculated numerically.