https://repositorio.ufu.br/handle/123456789/17890 2026-08-20T04:29:58Z https://repositorio.ufu.br/handle/123456789/49679 Title: Uma Análise Detalhada do Funcionamento de QR Codes 2026-03-20T00:00:00Z https://repositorio.ufu.br/handle/123456789/49651 Title: Análise paramétrica e projeto de superfícies seletivas em frequência para aplicações na banda n78 do 5G Abstract: This work presents a parametric analysis and the design of Frequency Selective Sur- faces (FSS) aimed at operation in the n78 band (3300 to 3800 MHz) of 5G telecom- munications networks. The main objective of this study is to evaluate how variations in the geometric parameters of different metallic scatterers and the properties of dielectric substrates influence the performance and electromagnetic response of these structures. To circumvent the high computational cost of full-wave simulations during the synthesis phase, an iterative analytical simulator named "FSS Explorer"was developed, based on the Equivalent Circuit Model (ECM). Through this software, two distinct topologies of band-stop elements were analyzed and optimized: Square Loop and Jerusalem Cross, aiming to tune the fundamental resonance frequency to 3.55 GHz over various commercial laminates. The design validation was performed through cross-comparison of the analytical data with rigorous simulations in the Ansys HFSS software. The results attest to the excellent predictive accuracy of the analytical equations in determining the center frequency, especially in elementary geometries such as the Square Loop, consolidating the co-simulation methodology and the developed tool as highly efficient instruments for reducing the time and computational effort in the pre-design of spatial filters for 5G. 2026-07-30T00:00:00Z https://repositorio.ufu.br/handle/123456789/49506 Title: Desenvolvimento de um manual didático para projeto e fabricação de placas de circuito impresso (PCI) Abstract: This Final Course Project presents the development of an educational manual on Printed Circuit Board (PCB) design and manufacturing techniques, intended for beginners and students in the field. The manual was developed based on fundamental concepts of electronics, good practices for PCB layout and routing, and an introduction to software tools used in PCB design. The study covers basic principles of electronics, the main electronic components used in printed circuit boards, and the structural elements of a PCB, such as traces, pads, and vias. It also discusses common design errors and technical criteria for trace width sizing. In addition, this work presents some of the main software tools used to support PCB design, as well as the most commonly used PCB manufacturing processes and materials. The proposed manual aims to provide clear, accessible, and illustrated instructional material to help beginners understand the stages of PCB design and manufacturing, contributing to the prevention of common errors and the development of practical skills in electronic circuit prototyping. The manual also includes guidelines for soldering through-hole (PTH) components, highlighting good practices required to ensure reliable, high-quality electrical connections. 2026-07-24T00:00:00Z https://repositorio.ufu.br/handle/123456789/49480 Title: Antena de microfita multimodo (TM03/TM11) com ganho e largura de banda aprimorados para 5G em 3,5 GHz Abstract: This work presents the design, analysis, and experimental validation of a microstrip antenna developed for operation in the 3.5 GHz band for fifth-generation (5G) wireless communication systems. The proposed antenna is based on the controlled combination of higher-order resonant modes in a rectangular patch modified by metallic shorting vias, enabling the simultaneous excitation of the TM03-like and TM11-like modes. The introduction of these vias alters the electromagnetic boundary conditions of the resonant cavity, bringing two resonances closer together and producing a dual-resonance response responsible for bandwidth enhancement. Initially, a reference antenna operating in the fundamental TM10 mode was analyzed based on the cavity model and full-wave electromagnetic simulations performed in Ansys HFSS. Then, the structure was redesigned for the target frequency range through the systematic adjustment of its geometric parameters, with special emphasis on the W/L ratio, identified as the key variable for controlling the frequency spacing between the excited resonant modes. The simulated results showed a 14.65% fractional impedance bandwidth for the criterion |S11| ≤ −10 dB, covering the frequency range from 3.29 to 3.81 GHz, with realized gain varying from 7.21 to 9.56 dBi and reaching a peak value of 9.62 dBi. The experimental validation of the fabricated prototype, in terms of |S11|, showed good agreement with the numerical predictions, yielding a measured bandwidth of 16.03%, from 3.27 to 3.84 GHz. In addition, the simulated radiation patterns exhibited stable behavior over the operating band, with predominantly broadside radiation and no significant sidelobes. The obtained results demonstrate that the adopted modal-combination strategy is an efficient approach for developing microstrip antennas with enhanced bandwidth, relatively high gain, and simple geometry, thus properly meeting the operational requirements of the 3.5 GHz 5G band. 2026-04-15T00:00:00Z