Design and Construction of a Piezoelectric Point Actuated Active Aperture Antenna

Abstract

In this research, an antenna’s far field radiation pattern is controlled by controlling the shape of a sub reflector in a Cassegrain antenna system. The antenna is actuated using multiple point actuators in contact with the reflector surface. A lead sarcomata titan ate (PZT) stack coupled with a friction-based compliant mechanism gives the point actuators used in this design an advantage over similar studies using PZT bimorph or PAD actuators. The main advantage stems from the fact that the displacement can be maintained without the continuous application of voltage. An electromechanical model is used to describe the motion of the stack, and the friction based compliant mechanism is modeled similar to power screw-type actuators. A combined finite element-electromagnetic analysis code is used to determine the desired shape of the reflector and the corresponding actuator displacements. The final shape of the reflector is verified using stereo photogrammetry.