DragOnFly — Electronically steerable low drag aeronautical antenna

This paper presents design considerations for the development of wide-scanning antennas for on-craft satellite communications. A scanning coverage of 80° is required for this application over a 15% fractional bandwidth in Ka-band. A solution based on a phased array illuminating a passive superstrate is identified as the most promising. A fully-electronic beam-scanning is considered in order to reduce the overall thickness of the antenna architecture by avoiding mechanical rotational supports. This is beneficial for the application since a reduced thickness corresponds to a lower drag. Two kinds of superstrates were investigated, a flat solution and a flattened dome. In both cases, the deflecting structure is illuminated by a phased array and is represented as a surface characterized by an optimized phase shift distribution that allows to maintain a high gain level up to very large scan angles. A flatter gain profile compared to a typical cosine scan loss for planar phased arrays was achieved in both cases. Attention was devoted to the minimization of the thickness, which was significantly reduced in comparison to classical dielectric dome solutions.