A Double-OAM-Mode Helical Antenna

Traditional helical antennas are modified to generate Orbital Angular Momentum (OAM). Compared with the poor gain or large sizes of most existing OAM antennas, the proposed helical antenna realizes a sufficient gain within a limited dimension, which makes it promising in practical application. As an example, a prototype is designed and simulated, which multiplexes OAM of
l
=2 and 3 on 5GHz (/ is OAM mode number), and its total size is about 80mm×80mm×25mm. Simulating result shows that its peak gain reaches 8.9dB and 8.2dB on 5GHz, for
l
=2 and 3 respectively, while the peak gain of most existing OAM antennas with similar electric size are below 5dB.