The Miniaturization of a Partially 3-D Printed Quadrifilar Helix Antenna

In this paper, the design and implementation of a quadrifilar helix antenna are presented where the four arms are 3-D printed. The antenna structure is miniaturized by resorting to a combination of two approaches. The first approach is based on loading the tips of the four helical arms with circular conductive disks. The size and location of these elements directly affect the antenna's operating frequency. The second miniaturization approach is based on incorporating an FR-4 dielectric material into the vacant space between the four arms of the quadrifilar helix. As a result, the length of the antenna is reduced by a ratio of 43%. The quadrifilar helix antenna is also designed on top of a ground plane with an optimized conical shape and topology. The antenna is partially fabricated using 3-D printing additive technology, where measurements show great agreement with simulated results.