Projeto e desenvolvimento de uma ULA com quatro elementos em microfita para aplicação em RTLS

Abstract

This work presents the design of a Uniform Linear Antenna that operates in the Bluetooth frequency range; and the initial stage of signal processing to determine AoA in RTLS applications. The project aims to serve as a basis for other more complex implementations. The ULA assembly consists of four copper patch elements with a thickness of 35 mm, arranged at a spacing of 0.35l on a 1.5 mm dielectric of fiberglass and epoxy resin tall. The array operates satisfactorily in the corresponding band between the frequencies 2402 MHz and 2480 MHz; the polarization of each element is circular, obtained by means of cuts in the corners of one of the diagonals of the patch, which allows the reception of the signal from emitters with linear polarization, regardless of its orientation; the power supply of the elements is individual, carried out by means of coaxial connectors and occurs when their internal conductor crosses the dielectric and is connected directly to the patchs; the set is unidirectional with forward pointing, having a maximum gain per element of 3.35 dB and a half power angle of 94◦. In the project presented here, the antenna is only used in the receiving function, but it can be used for transmission. The system is designed to operate at a characteristic impedance of 50Ω, which is currently the most widely used universal standard. Using the Ansys HFSS software and the MUSIC algorithm, the required signal incidence angle for RTLS was estimated from 0◦ to 180◦. This work is based on the theoretical knowledge available in the bibliography, personal contributions, results obtained through simulation and the measurements carried out in the tests carried out on the antenna prototype.