The helix antenna is a travelling wave antenna, which means the current travels along the antenna and the phase varies continuously. Helix antennas (also commonly called helical antennas) invented by John Kraus give a circular polarized wave. Helix antennas are referred to as axial-mode helical antennas. The benefits of this helix antenna are it has a wide bandwidth, is easily constructed, has real input impedance, and can produce circularly polarized fields...
Helix (Helical) Antenna Design