Nonlinear Constrained Beamforming Algorithm for Circularly Polarized Phased Arrays

In this letter, a beamforming algorithm based on least-squares problem subjected to nonlinear constraints is proposed. The formulation allows the main beam direction, polarization, sidelobe level, and nulls positioning control. For validating the algorithm, the system composed of a circularly polarized microstrip antenna array and a microwave beamforming circuit was manufactured and characterized.