Design of Uniformly Excited Unequally Spaced Antenna Arrays by Using Nonlinear Optimization

Numerous methods for the design of antenna arrays are based on optimization techniques. If the design problem can be expressed in a convex form, convex optimization is applied. If such is not the case, iterative or heuristic methods are used. On the other hand, the methods for nonlinear optimization have been rarely used in antenna array design. Nevertheless, these methods are attractive because they allow adapting the design problem for available solvers very easily. In this letter, we consider the application of methods for nonlinear optimization in the design of uniformly excited unequally spaced arrays with maximum directivity and maximum beam collection efficiency. We illustrate the effectiveness of these methods in solving the problems at hand as well as in improving the results obtained by other methods, where such improvement is possible.