Sidelobe-Level Minimization With Power Gain Constraint via a Wide-Beam Antenna Array

Abstract

To minimize the sidelobe level (SLL) of a wide-beam antenna array, the conventional approaches usually solve the shaped-beam pattern synthesis (SBPS) problem. These SBPS-based approaches focus on synthesizing a beam pattern that is similar to the desired one. However, the power gain except the beam shape is also an important concerning factor in array applications. This letter proposes an SLL minimization approach to obtain a lower SLL while achieving the similar minimum power gain in the wide-beam mainlobe as being obtained via the SBPS-based approaches. The proposed approach takes the power gain instead of the beam shape as the cost function and set up the synthesis optimization problem. An auxiliary variable is introduced to relax this nonconvex formulated problem into convex form. As a result, the original optimization problem can be solved iteratively. Even though the optimal solution cannot be theoretically guaranteed, numerical examples demonstrate that the proposed approach is able to further suppress the SLL by more than 10 dB for the flat-topped beam pattern and more than 3 dB for the cosecant squared beam pattern.