Method of performing beam compression process on antenna pattern of radar

A method of compressing the beam width of the antenna pattern of a radar system, comprising the steps of:

• providing an antenna system comprising a main antenna for transmitting and receiving radio waves and one or more pairs of dedicated receiving sub-antennas which are disposed at both sides adjacent to said main antenna in the direction of the beam width to be compressed of said main antenna such that the directions of the beam axes of said sub-antennas coincide with the direction of the beam axis of said main antenna;
• scanning the antenna beam of said antenna system in the direction of said beam width to be compressed, and receiving by the main antenna and sub-antennas the radio wave which was transmitted by the main antenna and reflected by scattering objects and has finally come back;
• converting the respective received signals received by the main antenna and the sub-antennas to power signals;
• performing double differential processing with respect to the scanning angle on the received power signals received by the main antenna and the sub-antennas, respectively, thereby producing double differential coefficients of the received power signals associated with the main antenna and the sub-antennas, respectively;
• calculating the phase difference between the received power signal received by the main antenna and the received power signal received by the sub-antennas;
• and
• outputting the received power signal received by the main antenna as a final output signal only if the conditions that both said double differential coefficients of the received power signals associated with the main antenna and the sub-antennas be equal to or less than predefined corresponding positive real number values and that said phase difference be equal to or less than 90.degree. are satisfied, and outputting a zero signal as the final output signal if said conditions are not satisfied.