Design of an ultra-wideband omnidirectional and polarization insensitive flower petal antenna for potential ambient electromagnetic energy harvesting applications.

Developing a polarization insensitive, omnidirectional, and ultra-wideband (UWB) antenna is highly desired for improving the utilization of freely available electromagnetic (EM) radiation energy. In this study, we have designed an UWB antenna based on tapered flower petals and numerically analyzed to show that it is a promising candidate for energy harvesting applications in the infrared (IR) to UV-visible regime. The impacts of design strategy and parameters on the absorption performance are studied numerically. The antenna shows a high performance in both bandwidth and absorptivity (average absorption of 84.5% spanning a broad range from 25 to 800 THz) under normal incidence of plane waves. To get a better understanding behind such high and UWB absorption mechanism, we investigated the electric field (E-field) distribution over the structure. The antenna also generates less than 5% absorption deviation between normal to 45° incident angle and 0.05% absorption deviation between 0° and 90° polarizations for both transverse electric (TE) and transverse magnetic (TM) modes. This new design aspect and the numerical findings unfolds the new direction for numerous EM wideband applications such as THz technology, photo detection, bolometric sensing, camouflaging, spectral imaging, and ambient EM energy harvesting applications.