الفهرس 
صفحة العنوانOnly 14 pages are availabe for public view
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Abstract
Optical nanoantennas (NAs) are nanostructure-based devices that are used as mediator to convert free optical radiation into localized energy and vice versa. Due to their extraordinary properties, the NAs can play vital rules in several applications such as sensing, photovoltaics, and energy-harvesting. Therefore, various optical nanoantennas have been studied like Yagi-Uda, log-periodic, spiral NAs, etc. from a multitude of suggested NA concepts, the Yagi-Uda stands out by its efficient unidirectional light emission and enhancement.
In this research, all dielectric Yagi-Uda NAs based on different element shape are introduced and analysed to maximize the directivity and radiation efficiency. The studied element shapes include triangular, diamond, hexagonal, cube, square, rectangle, ellipsoid, and elliptical cylinder shapes. The NAs parameters for each design are optimized using particle swarm optimization (PSO) algorithm to achieve high directivity at a wavelength of 500 nm for wireless point-to-point applications. The designs are numerically analysed using 3-D finite difference time domain method (3-D FDTD) via Lumerical software package. To illustrate the performance of the proposed antennas, different radiation parameters such as field profile, radiation pattern, directivity, and radiation efficiency have been studied. Moreover, a tolerance of ±5% is calculated to consider the imperfections that may appear in the fabrication process at a nanoscale.