Navegando por Autor "Oliveira, Elias Marques Ferreira de"

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Caracterização de uma família de ressonadores planares: estruturas circulares autossimilares para aplicação de circuitos de micro-ondas
(2022-10-14) Bernardo, Helton Silva; Oliveira, Elias Marques Ferreira de; http://lattes.cnpq.br/2576044894885888; http://lattes.cnpq.br/0376996218317422
The present work aims to develop and structure a family of circular and self-similar resonator devices based on modeling by microstrip technique with planar structures to determine resonances and frequency bands, allowing to identify and locate the structuresthat resonate. The methodology behind thisstudy is described in two parts: In the computational elaboration procedure (structuring and parameterization) and the simulation in different aspects. Mathematical modeling of the family of resonator devices was carried out, the parameters of wavelength and radii of the central and adjacent resonator rings were calculated, as well as the boundary conditions for the family of resonators in a computational environment. The structures that showed adequate resonance levels were characterized by band-stop filters through the scattering parameters. The construction of the characteristic filters took place by configuring the parallel of electrical network topologies (low-pass and/or high-pass) with similar responses. The main and adjacent rings were repaired to analyze the maximum transmission and maximum resonance. This study also analyzed the surface current distributions for structures that presented different behavior in relation to their resonances. In this way, the results show: resonance in different frequency bands, tuning of parameters for maximum resonance by reparametrization and the dynamics of surface currents in the resonator rings.
Design e simulação de um acoplador planar reconfigurável para aplicação em sistemas de telecomunicações em micro-ondas
(2024-10-10) Santos, Cleberson Andrade da Silva; Oliveira, Elias Marques Ferreira de; http://lattes.cnpq.br/2576044894885888; http://lattes.cnpq.br/2197671175992514
The growing demand for advanced electronic devices for communication has driven the development of microwave technologies capable of operating in multiple frequency bands. Initially, wireless communication was limited by fixed transmissions and low-frequency bands, but technological innovation has enabled expansion to microwave frequencies, ranging from 3 GHz to 300 GHz. Among the critical components in this range, filters, duplexers, and hybrid couplers stand out, being essential for the management and distribution of electromagnetic power in communication systems. However, as technological demands have evolved, the need for multifunctional devices capable of operating in more than one frequency band has become crucial. Directional couplers, which traditionally have four ports and are used to couple a specific amount of electromagnetic power, are classic examples of couplers designed to divide power equitably among the ports and are known as hybrid couplers. A specific type of known coupler is the branch-line, widely applied in circuits such as amplifiers and balanced mixers. Innovation in this type of device has focused on the integration of artificial transmission lines (ATLs) to enable multiband operation of these couplers. ATLs are designed to simulate the behavior of conventional transmission lines in various frequency bands and are crucial for the development of devices with multiband operating capabilities. This work proposes the investigation and development of new techniques for the design of branch-line hybrid couplers, focusing on creating reconfigurable versions, as well as improving the relationship between operating frequencies and reducing the size of the devices. The approach aims to optimize the performance of couplers, meeting the growing demands of modern communication systems, providing more versatile and efficient solutions for microwave applications. The project will be carried out with the aid of electromagnetic simulation software, and the behavior of the switching elements will be modeled through equivalent circuits, allowing a detailed and accurate analysis of the device characteristics.
Implementação de sistema PI para controle de temperatura utilizando o método da frequência de Ziegler-Nichols
(2023-04-27) Alves, Max Matias; Oliveira, Elias Marques Ferreira de; http://lattes.cnpq.br/2576044894885888; http://lattes.cnpq.br/9969391867572722
Industrial process controllers are increasingly needed, and the most used are the on-off controllers and the PID (proportional-integral-derivative), which are widely used in industrial processes. The general purpose of this article is to implement a prototype of a temperature control automation system with PID, reviewing tuning concepts and methods in order to compare the effectiveness with the on-off controller. The on-off type control has two fixed positions, on or off, since the PID corresponds to the relationship between the read variable and the setpoint. There are several methods of tuning this type of controller including empirical methods to the most refined; but that usually involves three steps: disturbing the process, analyzing and quantifying the system's response to the disturbance, and then tuning the controller parameters. The frequency method proposed by Ziegler-Nichols consists of determining the critical gain and the critical period to obtain the tuning parameters. The apparatus for the experiments consisted of a thermal box to simulate the environment, with a temperature sensor inside and an incandescent lamp to generate disturbance of the variable, a fan to blow air into the environment, and the embedded system containing an Arduino and an electrical circuit board. Applying the proposed method to the experiments, we obtained the results for the P, PI, PID and on-off controls. When analyzing these results, it was verified that for such conditions, the best controller was the PI type.
Projeto e implementação de um conversor cc-cc boost com controle Proporcional-Integrativo-Derivativo (PID)
(2023-04-26) Lima, Bruno de Freitas; Oliveira, Elias Marques Ferreira de; http://lattes.cnpq.br/2576044894885888; http://lattes.cnpq.br/4293028027442685
This work proposes the analysis of PID controllers developed using a mathematical tool, pidtool, to define the controller parameters for controlling a boost converter. The boost converter is designed to ensure a 15V output with a fixed 5V input. Experiments without the use of controllers are performed to confirm the voltage level increase. When the controllers are implemented, an 8V setpoint is defined for the output to protect the connected components in case of potential failures, considering it is a prototype. Computational simulations and practical experiments are conducted using the proposed converter parameters to compare the step response of the proposed controllers. Finally, a discussion is held on the collected data, the applicability of the matlab pidtool in designing PI, PD, and PID controllers, and a brief discussion on future studies regarding the impact of different hardware types on control.