Radio Wave Propagation Through Vegetation

Vegetation is an indispensable feature of most outdoor wireless channel environments. The interaction between radio waves and vegetation has been researched for several decades. Because of the complex structure of the foliage, composed of randomly oriented trunks, branches, twigs and leaves, the involved physical process in the propagation of the radiowave through vegetation is complex. Accurate modeling of the propagation of radio waves through tree foliage, generally requires accurate electromagnetic description of the tree geometry, including its branches and leaves, valid over a wide range of frequencies. Originally empirical models were developed to describe the propagation of radio waves in the vegetation. In other approaches this interaction is analyzed using ray-based techniques. More recently theoretical –statistical and analytical– approaches became favorable. As it is discussed in the next section, major disadvantage of all these models is that the final outcome is basically presented by providing an excess attenuation to that caused by free space propagation.