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 zircamate titanate (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 PVDF 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.

Design, modeling, and optimization of mechanically reconfigurable aperture antennas

“…As the voltage increases, the stack elongates and the two halves of the threaded jaws move in opposite directions. As the voltage decreases, the stack and jaws return to their original position [26]. As the screw advances, the threaded shaft moves relative to the actuator body.…”

“…This cycle is repeated until the desired displacement is met. This actuator improves upon the standard piezoelectric stack by increasing the maximum deflection by five orders of magnitude [26].…”

“…This motion is shown by the difference between cycle 1 and cycle 2. To compensate for these differences, a simple closed-loop controller was developed [18]. Again, Fig.…”

Deflection model for corner-supported plates with segmented in-plane actuators

“…In [10,16], finite element models for simply supported rectangular PVDF laminates are studied. Control algorithms based on analytical and numerical laminate models are discussed in [2,3,13].…”

Efficient Shape Control of Distributed Reflectors with Discrete Piezoelectric Actuators

“…A major problem stems from the fact that once the antenna is deployed on orbit, the radiation pattern cannot be modified. If the shape of the antenna is allowed to change, however, this problem can be addressed (Washington and Silverberg, 1994;Theunissen et al, 1999;Yoon and Washington, 1999;Granger et al, 2000;Angelino and Washington, 2002). In this study the shape of the antenna surface is described by a set of linearly independent orthogonal functions called modes.…”