Path-length control for a reflector antenna using piezoelectric actuators and a focus adjustment mechanism

Abstract

A novel method for recovering antenna gains of a reflector antenna system using piezoelectric stack actuators and a focus adjustment mechanism is developed and its feasibility is investigated. Reconfigurable reflector antennas are promising technologies for high accuracy reflectors used for future high performance space missions. Piezoelectric stack actuators are good candidate for surface adjustment actuators for such reconfigurable reflector antennas in space, because they have no sliding portion. However, piezoelectric stack actuators are usually used for only pushing; therefore that causes some trouble in shape control of the reflector system. In order to overcome the problem, piston mode of wave front obtained by using piezoelectric stack actuators and the focus adjustment mechanism is utilized to make control inputs for the actuators positive values. In this method, a deteriorated wave front due to reflector deformations is adjusted to have new coherent wave front instead of recovering the original shape of the reflector. Some numerical simulations are carried out to investigate the feasibility of the developed method. The radiation patterns are analyzed for the corrected wave front by the developed method and that by the conventional shape control method using push/pull actuators. The results of these simulations show that the antenna gain is recovered adequately by using the developed method and the gain is almost same as that obtained by using the push/pull actuators. The effectiveness of the developed method is positively demonstrated by the comparison.