Comparison of measured scattering coefficient of dry soil at X-band with the scattering coefficient estimated using the dielectric constant

The soil is one of the natural earth material which is produced by withering of rocks. The soil is mix of sand, silt and clay with air pores. The compactness of soil depends upon the percentage of these constituents and the pore size. The dry soil has its dielectric constant which is independent of frequency and so the scattering coefficient also will be independent of frequency for pure dry sand. But in nature it is not so, it always has some percentage of moisture in it. The moisture will be due to presence of water which will be a combination of bound water and free water. More the percentage of moisture more is the presence of free water. But for dry soil there is no water and for natural dry soil the free water is very small and mostly it is bound water. The scattering coefficient will be different although soil is close to dry and also will vary with frequency due to presence of small quantity of free water present. The scattering coefficient has been measured for HH, VV, HV, VH polarizations. Separately using the values of the soil constituents the dielectric constant is estimated for pure dry sand. Using this dielectric constant the scattering coefficient is estimated for different polarization. For estimation of scattering coefficient the small perturbation model is used which is applicable for slightly rough surface. The measured values of scattering coefficient is compared with estimated values of scattering and the error analysis is done.