الفهرس 
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Abstract
Abstract
This thesis presents an optimized antenna design in Terahertz band using different types of optimization techniques such as Genetic Algorithm (GA), Particle Swarm Optimization (PSO) algorithm, Central Force Optimization (CFO) algorithm, Gravitational Search Algorithm (GSA) and Chaotic Fruit Fly Optimization Algorithm (CFOA). The main objective function of our optimization algorithms is the maximization of the antenna gain to be able to overcome the atmospheric attenuation occurred in such high frequencies and/or the minimization of the return loss to minimize the mismatching loss and achieve better impedance matching.
At first, the Yagi-Uda antenna design and the impact of the optimization on the antenna performance have been studied. It is found that the antenna performance is highly improved by using different optimization algorithms. As a comparison between different algorithms, the CFOA algorithm has proved its strength and high convergence capability more than the MCFO, GA and GSA optimization algorithms.
Furthermore, a modified Yagi-Uda antenna structure has been designed and developed. The performance of the modified antenna is optimized using CFOA algorithm. The optimization results are compared with those obtained using the PSO algorithm. As expected, the CFOA algorithm results are better than that obtained using the PSO algorithm. The high gain and the low return loss with the small antenna size give good opportunity for the proposed antenna structure to be used in the THz various applications