Practical constraints on reactively steered antenna arrays

Reactively steered antenna arrays (RESAAs) can be steered electronically by varying their load impedances. To maximize radiation efficiency, the load impedance must be reactive to avoid ohmic losses. A simple means to implement the reactive loads is with varactors. This places further constraints on the load in that the load impedance must not only be imaginary but also negative. In this paper, prior work is reconsidered in light of this practical constraint. Simulations are performed to evaluate the beam steering and interference nulling of a hexagonal array with these constraints. The complexity of the array is minimized while providing performance suitable for some applications.