Estudo da conversão de polarização linear-circular em antenas dual-band para leitores RFID portáteis usando metasuperfícies miniaturizadas

Abstract

This work aims to propose a new structure able to convert signals linearly polarized generated by a microstrip antenna for circularly polarized signals at two operating bands (2.45 GHz and 5.8 GHz), for use in portable RFID readers, using two miniaturized metasurfaces. In order to study the behavior of the proposed structure, three different layouts are used. First initial simulation tests are made, using the first metasurface coupled to the antenna. Then, the antenna is tested coupled to the second metasurface. Posteriorly the antenna is coupled to the two metasurfaces. The structures are analyzed numerically through ANSYS HFSS™, and to validate these results, the structures are characterized experimentally. The characteristics of transmissions simulated and measures are presented. A good agreement between simulated and measured results was obtained. The structure proposed here has the advantage to meet desired characteristics in two bands of interest, obtaining excellent values of return loss wideband, as well as the axial ratio, being a simple structure to be constructed and with low cost.