Two-way Planar Array Radar with Diamond- and X-shaped Configurations for Sidelobe Suppression

Abstract

The undesirable sidelobes in the pattern of a two-way radar antenna array is usually minimized by thinning several elements in the receive or transmit arrays. The thinning process is performed randomly on all array elements by using an optimization algorithm, with the computation time being significant due to a large number of combinations that need to be examined. In this paper, sidelobe suppression in a two-way array pattern is achieved by properly structuring the received array's elements into a diamond- or X-shape, such that its far-field pattern has exact null regions toward the directions of the sidelobe regions of the transmit array pattern. Then, multiplication of the null regions of one pattern with the sidelobe regions of another pattern results in a great reduction in the sidelobe levels of the resultant two-way array pattern. The transmit array structure was fixed as a standard rectangular shape, which has two dominant regions of the sidelobes along the horizontal and vertical lines on the array aperture. To obtain ultra-low sidelobes, the receive array structure should have nulls on these lines, and their sidelobe regions should be located on the diagonals of the array aperture. To meet these alignment conditions, the received array structure was designed as a diamond- or X-shaped structure. It was observed that the proposed configurations offer potential to suppress the sidelobe levels to more than -51 dB and the complexity ratio was lowered to 43%, with both values being much lower than the ones available in the literature.