Abstract
Low-frequency active microwaves allow one to investigate the sub-surface down to several meters under some conditions. So far, few studies were conducted in this field. This paper addresses the problem of attenuation due to the sub-surface propagation phenomenon. The theoretical study about soil propagation predicts attenuation which strongly depends on incidence angle, on polarization, and most of all, on moist content. The simulation of the attenuation was done for various soil types for different polarizations. In P-band (435 MHz), we have obtained a penetration depth up to 17 meters for a dry soil before 3 dB attenuation of the incident wave.