Archimedean spiral antenna on moveable ground plane for UWB applications

In this paper we investigate the performance of a two-arm Archimedean spiral antenna over a moveable conducting ground plane (GP) for UWB applications. The performance of the antenna in terms of return loss, gain, axial ratio and radiation pattern are analyzed when the electrical separation between the spiral arm and ground plane is maintained at 0.25 λ over the frequency range 3.1 - 10.6 GHz. The results demonstrate that as physical separation of the GP reduces, the overall antenna's performance deteriorates. The results show that gain of the spiral antenna can be increased more than 9 dB with -10 dB operating bandwidth of more than 100%. The simulated and measured results have shown good agreements.