Axial-mode elliptical helical antenna with variable pitch angle

To improve an elliptical cross-section helical antenna's radition performance, an elliptical helical antenna with a variable pitch angle is proposed. Its radiation patterns are simulated by the moment method and FEKO software. The results show that its circular polarisation as well as its directivity can be improved compared with an elliptical helical antenna of the same coil number, axial size and arm length.