Joint Optimization of Active and Reactively Loaded Passive Dipoles for Beam Steering for Future Wireless Applications

In this article, we develop a novel algorithm for jointly optimizing the excitation voltages and the load impedances of arbitrary arrays of multiple active and multiple reactively loaded passive dipoles. The proposed algorithm hinges on obtaining a closed-form expression for the optimal excitation voltages of the active elements as a function of the load reactances. Noting that the array gain is a nonconvex function of these reactances, we develop an upper bound on the array gain and we use this bound and the excitation voltages that achieve it to guide the search for the optimal load reactances. Our numerical results show that the proposed technique tends to achieve the upper bound within a relatively small gap.