MODELING AND CONTROL OF ACTIVE APERTURE ANTENNA

Abstract

Recently, a lot of interest has been generated in the area of intelligent system and structure because of enormous possibility in vibration and acoustic control, shape control and health monitoring of space structure. A smart structure involves distributed actuators, sensor and control system. The present study deals with a class of antennas capable of variable directivity (beam steering) and power density (beam shaping). The actuation of these antenna structures is achieved by attaching Lead Zirconate Titanate (PZT) and Polyvinylidene Fluoride (PVDF) actuator layer to Aluminum substrate. A voltage drop across the actuator materials causes the material to expand or contract. This movement of actuator causes inward and outward moment of antenna structure, which causes the structure to change shape. The shape changes due to bending causes beam steering and beam shaping of coverage area. To understand the working concept of active aperture antenna, the model of antenna with plate structure is constructed using thin plate theory. The deflections of antenna structure offer beneficial changes in the radius of curvature and shape change of reflector surface. For modeling, this type of structure commercially available FEM software such as ANSYS is used. The obtained results are validated with numerical results documented in the literature