Desenvolvimento de uma ferramenta computacional para síntese de redes de antenas

Abstract

Here we report the development of computational tools based on the particle swarm optimization (PSO) applied in the synthesis of radiation patterns of linear antenna array. The synthesis aims to determine the currents (amplitudes and phases) of the elements that compose the array. The calculated currents must produce a radiation pattern that affects the design specifications. In this work, the tool was developed in Matlab software, and allows pointing the beam in a particular direction, and control the level of side lobes. This work was essentially developed in three stages: the choice of optimization method to be used; development of the tool; validation and experiments. To set the optimization method to be used in the tool, two methods were studied, the genetic algorithm (GA) and Optimization Ant Colony (ACO). Among them the PSO, was chosen because of its effectiveness. After the development of the tool, it has been applied to linear array isotropic elements, isolated element multiplied by the array factor and an array with active elements. In the experiments, the simulation for an array with 7 active elements, in order to synthesize three different applications: pattern of a cardioid; switched beam system; system with squared cosecant shape. To validate the method, the specified diagram compared to a desired appointment and simulated in the software HFSS and a diagram in the squared cosecant function shape with the simulated network diagrams in HFSS and optimized by tool. In addition to these enhancements both array with active elements used in a Unmanned Aerial Vehicle (VANT) have been optimized to ensure communication between it and the ground station. Despite the simulations for different applications, the real purpose of the synthesis tool, is to serve as a generic program, where any user with different applications can use. Having that in mind, a graphical interface has been programmed to assist the user with the synthesis tool; the user enters only the array parameters and the number of iterations and particles. The interface will display the synthesized diagram and evolution curve, if desired by the user, it may save the excitation coefficients of the elements, and the total electric field.