Some peculiarities of the HF signal when locating the sea surface

Obtaining information about the state of the sea surface using HF radars has been the subject of intensive studies over several decades. In most of the theoretical investigations a plane wave with a definite wave vector is taken as the incident wave. In real conditions, however, a wave beam of finite width is incident on the scattering sea surface, which should be taken into account when investigating the form of the spectrum and processing it to derive information about the sea surface. This paper investigates the scattering of electromagnetic waves from the sea surface with due regard for the finiteness of the beam of the receive and transmit antennas; a numerical simulation is used to investigate the of these beams on the spectrum structure of the received signal. In addition, a study is made of the influence of the finiteness of the coherent integration time and the spectral width of the sounding signal on the form of the received spectrum.