The Radio Waves Propagation and Scattering

In this work the results of the theoretical and experimental researches on the field strength calculation near the earth surface and the radio-waves scattering in turbulent atmosphere are presented.

The Hata model and the International Telecommunication Union (ITU) recommendations were analyzed; the accordance between ITU recommendations and diffraction theory was established. It is considered that the calculations based on the V.A. Fock-s diffraction formula meet ITU recommendation to the diffraction horizon. Therefore the usage of the diffraction theory is quite justified for the field strength forecasting in VHF and UHF, with allowance for the terrain clearance angle correction recommended by ITU.

The equivalent Earth radius concept, valid for the linear model of atmosphere, has been generalized on the exponential model. It was obtained that the radio waves refraction condition has the strongest influence on the field strength near to the earth surface. The radio-waves propagation in the ground layer of inversion is considered and all necessary formulae for the path loss calculation are introduced.

The scattering signal registration provides an opportunity to receive the path loss values near the terrestrial surface with allowance for the landform features. After experimental results averaging it is possible to define the refraction conditions in the atmosphere ground layer. The path loss experimental values are in consistency with the theoretical calculations results.

In this work, modern representations about turbulence atmosphere are described and it was shown that the wave and turbulent movements separation problem could be solved by the scattering spectra analysis. Results of the theoretical and experimental researches of the backscattering from the atmosphere have been presented.