Error Suppression via Tension for Flexible Square Antenna Panels and Panel Arrays

Abstract

The concept of passive surface error control via tension is explored for flexible square panels and for a rectangular array of such panels suspended with four catenaries. The panels are 1 mm thick 1 m square graphite-epoxy composite plates with a four-ply symmetric layup. Individual panel response to a uniform through-thickness temperature gradient field both alone and combined with in-plane tension (stretch) are examined. When integrated into a grid (a simple phased array configuration), the effects of a transient slew are considered. Characteristic responses are identified and studied symbolically as well as numerically. The results demonstrate the feasibility of combined global and component-level error suppression for the considered structure, exercised singularly by global prestress that also maintains the integrity of the tension structure. Limited attention is paid to mission-specific issues such as stowage and deployment. Assuming an X-band radar context, surface errors are related to a 1 mm limit. Out-of-flatness is evaluated with three metrics relevant to different aspects of signal processing: the maximum depth of the deformed surface, its maximum lateral deviation from the best-fit plane, and the phased-array radiometric rms surface error.