Asymmetric Beampattern Synthesis for Rectangular Planar Array via Window Function Design

In this paper, we propose a window function design to synthesize beampattern for uniform/sparse rectangular planar array (RPA) with strict constraints on array gain loss to ensure the performance of target detection/tracking, parameter estimation, etc. The array structure under consideration in this work is generated by the Kronecker product of two uniform/sparse linear arrays, thus referred to as RPA-K. In addition to the common symmetric beampatterns, the proposed method is able to synthesize asymmetric beampatterns to enhance interference/clutter suppression in practical scenarios, such as airborne phased array radar (APAR). Rather than designing the beamforming weight vector for each steering direction separately, this work aims to design a window function for multiple steering directions, as a result significantly reducing the computational cost. To design such a window, an iterative alternating optimization algorithm (IAOA) with dynamic allocation of gain loss is proposed to handle the resultant non-convex problem, and its convergence is studied. Compared with directly designing one window function, the proposed method greatly reduces computational complexity by decomposing the window function into two parts. Finally, numerical simulations verify the effectiveness of the proposed window function comparing with the classical adjustable window functions (CAWFs).