Deployable Bistable Composite Helical Antennas for Small Satellite Applications

Abstract

An ultra-compact deployable helical antenna is presented, designed to enhance space-based \nreception of Automatic Identification System signals for maritime surveillance. The radio frequency \nperformance (i.e. peak gain and directionality) is simulated at 162 MHz using ANSYS \nHigh Frequency Structure Simulator and evaluated over a range [0.5–8] of helical turns. Established \nand commercially available omnidirectional antennas suffer interference caused by \nthe large number of incoming signals. A 7-turn helix with planar ground plane is proposed \nas a compact directional-antenna solution, which produces a peak gain of 11.21±0.14 dBi and \nhalf-power beam width of 46.5±0.5 degrees. Manufacturing the helical structure using bistable \ncomposite enables uniquely high packaging efficiencies. The helix has a deployed axial length \nof 3.22 m, a diameter of 58 cm, and a stowed (i.e. coiled) height and diameter of 5 cm — the \nstowed-to-deployed volume ratio is approximately 1:9,800 (0.01%). The use of ultra-thin and \nlightweight composite results in an estimated mass of 163 grams. The structural stability (i.e. \nnatural vibration frequency) is also investigated to evaluate the risk an unstable deployed antenna \nmay have on the radio frequency performance. The first vibration mode of the 7-turn \nhelix is at 0.032 Hz indicating the need for additional stiffening.