Optically controlled antenna, providing continuous coverage

Abstract

An array antenna is steered by moving a set of optical fibers of different optical length between a number of light signal sources and an array of antennas. By changing the lengths of the optical paths of the different light signals sources, the wave front can be steered. The light signal traverses three sections of optical delay lines with at least one selectable optical length. In the first section, light signal from a point source travels through a first optical delay line and a lens to diverge and collimate the light beam with increased cross section. The collimated light beam is focused by second lens and incident one second optical line of selectable optical length. The light beam exiting from the other end of the second optical line is collimated again by a third lens to face a third optical line. The collimated light exiting from the second optical line is focused again by a fourth lens to feed the third optical line, which is connected at the other end to one element of the antenna array. This defocused and focused arrangement allows the steering of the radiation pattern to be continuous and not intermittent. The second fiber optic lines are mounted on a rotatable disk with respect to the first and third optical lines which are terminated on a concentric stationary disk. The antenna array can serve both for a transmitter or a receiver, which can be a signal processor.