Enhanced-performance UWB antenna using stacked EBG surfaces

Circular monopole printed antenna can be designed to cover an ultra wide bandwidth (UWB) of 4:1 ratio with large gain variation over the band. Electromagnetic band gap (EBG) structures/surfaces are used to enhance antenna radiation by generating coherent radiation that adds to the antenna pattern to produce higher gain. A conventional EBG surface has a narrow-band, centered at the resonance frequency that is a function of its dimensions. Stacked EBG structures, on the other hand, can be designed to cover very wide bands that match the operating bandwidths of the UWB antenna. This paper presents the enhanced performance of a UWB circular monopole antenna, achieved through the use of a 3-layer stacked EBG structure. Reflection phase performance of the EBG structure is shown to cover the wideband, and results in higher gain for the monopole over most of the band. The results are compared with a Vivaldi antenna operating at the same wideband to show the higher gain of the lower-profile EBG-enhanced printed circular monopole.