V.V. Zadorozhnyy, A.Yu. Larin, A.V. Litvinov, A.S. Pomysov

The article describes a method for the narrowing the beamwidth of digital antenna array based on processing multiple beams with maximums directions are spread apart by an amount equal to or greater than the antenna patterns beamwidth. The results of simulation parameters in the DAR with non-identical channels when using the proposed method are presented. The simulation results of the two methods for the narrowing the antenna patterns beamwidth based on the difference between the sum and difference beams - one of them for the construction of the sum and difference beams is used dividing the array into subarrays and the other is used independent beams, the direction of the maxima are spread apart by an amount equal to or greater than the antenna patterns beamwidth. Mathematical modeling results show that digital antenna array with non-identical channels with uniform amplitude and phase distribution within ± 0.5 dB and ± 5º, respectively, provided the beamwidth narrowing in 2.6 - 2.8 times and reduce the side lobe level up to 5 dB, depending on the direction of the resulting beam. When using a power function u=0.5 the method provides a reduction of beamwidth narrowing in 5.3 - 5.8 times and the reduction of side lobes up to 3.4 dB. Using the presented method makes it possible to increase the angular resolution of the radar in 2.6 - 2.8 times without increasing the overall dimensions of the antenna system. The presented method using independent beams has a higher resistance to non-identical channels of digital antenna array and offers up to 35 % more narrow resulting beam and 5 dB lower side lobe level than the method based on the division of the antenna array on the subarrays.