Spectral study of microwave attenuation in a larch forest stand for oblique wave incidence

In this paper the results of experimental study of radio- wave attenuation on in the case of oblique forest paths are presented. All the measurements were carried out at frequencies of 400, 600, 800 and 1000 MHz for linearly polarized waves, with the maximum horizontal distance being of 112 m. As a result of this study, two competitive wave propagation mechanisms were discovered. The first one describes exponential attenuation along the path obliquely crossing through forest medium, while the second suggests wave propagation in the lossless medium above the forest layer and subsequent wave scattering at the tree crowns, which are located above the receiver being placed near the ground in the forest.