Metamateriais aplicados ao aumento de ganho em antena Vivaldi

Abstract

This undergraduate thesis explores the application of three configurations of metamaterials in a Vivaldi antenna, with the intention of increasing the gain without modifying the antenna structure. The Vivaldi antenna in question features palm-shaped slots to optimize the bandwidth. The targeted bandwidth is 2.2 GHz, operating in the frequency range of 4.9 GHz to 7.1 GHz, which is the range used by WiFi 6. Simulation results show reflection coefficient values below -15 dB at 2.15 GHz bandwidth or 35.84% fractional bandwidth and a gain of 7.64 dBi. Three different metamaterial structures were employed to increase the gain and compare the structures. In the study of unit cells, parameters of phase shift in the incident voltage wave and the main parameter of phase delay of the metamaterial in relation to an angle of incidence were analyzed, so that it can convert a cylindrical wave generated by the source into a uniform wave at the output. The three metamaterial structures achieved a gain increase of 10.8 dBi for the first, 9.46 dBi for the second, and 9.36 dBi for the third at a frequency of 6 GHz. The bandwidths of the three structures were 1.93 GHz for the first, 1.51 GHz for the second, and 1.87 GHz for the third. Therefore, the results indicate that all structures allow an increase in the gain of the Vivaldi antenna while maintaining the antenna with an ultra-wideband.