Electromagnetic waves are polarized; the direction of the polarization corresponds to the direction of oscillation of the electromagnetic field. Typical and often used linear polarisations are: H (horizontally) and V (vertically) polarized waves of the plane of the electric field vector oscillations relative to the sensor coordinate system. The polarization state of a backscattered wave from a natural surface can be linked to the geometrical characteristics like shape, roughness and orientation and the intrinsic properties of the scatterer like moisture, salinity, density. The radar system is characterized by combination of polarization of transmitted and received pulse: HH, HV, VH or VV. Based on the polarization sent and obtained the radar systems are divided in three polarization modes. Single polarization refers to the same polarization transmitted and received; dual polarization, one polarization is sent and another received; or quad polarization, when system is able to transmit and receive all four types of polarization. When making a contact with a scatterer, the polarization of the EM-wave can change, depending on the geometrical and dielectrical properties of the scatterer. In order to get all necessary information about those changes, full polarimetric systems are required.