Development of Metaheuristic Optimization Algorithms for Antenna Synthesis with Array Factor Redefined.

Abstract

The present research work is aimed at application of nature inspired metaheuristic
optimization algorithms to antenna array synthesis with particular emphasis to linear and circular configurations. The main focus is to design the inter element spacings and the amplitude and phase of the excitations of these elements such that the undesirable sidelobe levels are minimized. This is further supplemented by some constraints specifically placement of nulls at prescribed locations and restricting the first null beamwidth apart from limiting the physical size of the antenna. Such study while pursued to determine the design parameters as stated above using the metaheuristic optimization techniques resulted in contributions to two specific domains, one in developing new variants of existing algorithms to conceptualize new shapes and the other one is concentrated on redefining the arrayfactor expression on a novel platform. From the view point of algorithms augmentation an Enhanced Ant Lion Optimization algorithm and a Restructured Animal Migration Optimization algorithm have been established along with Runner- Root algorithm which is applied to antenna array synthesis for the first time. Further on the other front, when optimization algorithms are being used, the objective function supposed to be minimized, comprises of arrayfactor expression. And during the investigation while the arrayfactor is revisited and analysed it unravelled few insights that successfully led to the derivation of two novel expressions; one from the fundamental concept while the other a highly innovative one is known as two element interaction theory is borrowed from circuit theory concept in electrical engineering. These new generic expressions have added a new dimension in arrayfactor framework which is capable of taking variation of any parameter that influences arrayfactor. The results obtained from the application of the proposed algorithms along with taking into consideration the generalised expressions for arrayfactor to construct the objective function in antenna array synthesis problems are highly impressive and inspiring. And such inferences have led to the formulation of the proposed algorithms have emerged as potential contenders in comparison with its counterparts in metaheuristic optimization domain.