Abstract
Communications present a major bottleneck for small-satellite functionality given their extremely small volumes and low power. This work addresses this gap by presenting an ultra-compact, high-gain deployable helical antenna designed for space-based reception of Automatic Identification System signals at 162 MHz for maritime surveillance. The radio frequency characteristics of helically curved ribbons are investigated and optimized through a parametric study of the helical and ground plane geometry. Square, planar ground planes of various size and thickness, and a range of helical ribbon widths are studied. Both are modeled as perfect electrical conductors using ANSYS High Frequency Structure Simulator. Simulation results indicate that the addition of a ground plane centered and positioned at the base of the helical antenna element: 1) reduces back lobe radiation and 2) enables optimization of the radiative performance through adjusting the antenna geometry i.e. the peak gain may be increased by 3.5% (on average) for each additional helical turn — 1-8 helical turns are simulated. The half-power beam width may also be improved indefinitely by adding more helical turns. The most focused beam presented, 40 deg, is produced by an 8-turn helix, which is 58 cm in diameter and has an axial length of 3.68 m. Two ground plane sizes are considered, with the largest, which is four times larger in area, producing 5% higher peak gain. Conversely, the ground plane size had negligible effect on the half-power beam width in long helices (i.e. >3 helical turns). Increasing the helical ribbon width in steps of 10 mm was found to improve the peak gain by 8% on average in long helices.