Shaped Power Pattern Synthesis with Minimization of Dynamic Range Ratio

The problem of synthesizing array patterns while reducing dynamic range ratio (DRR) of complex excitations is of great importance in practical applications since it enables active arrays to be more attractive by appropriately controlling the mutual coupling between the neighboring elements, as well as reducing the cost and complexity of the feeding network design. Unlike the commonly adopted DRR control technique, this paper focuses on minimizing the DRR of the excitations while synthesizing the anticipated array pattern, which results in a new nonconvex and nonlinear optimization problem because of its fractional objective function and nonconvex constraints. By introducing auxiliary variables, we derive an equivalent optimization problem that transforms the fractional objective function into a linear one, decompose the original optimization problem into several subproblems in each iteration, and simplify them as either single-variable quadratic unconstrained optimization or least-squares problems that are solved efficiently in each iteration. Numerical results with different radiation requirements are shown to demonstrate the effectiveness of the proposed scheme.