Banca de DEFESA: ISAAC BARROS TAVARES DA SILVA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : ISAAC BARROS TAVARES DA SILVA
DATE: 16/12/2019
TIME: 09:00
LOCAL: AUDITÓRIO DO CTEC
TITLE:

Development of NiFe2O4 Ferrimagnetic Material for Application in Microwave Communication Systems

KEY WORDS:

Ferrimagnetic resonator antennas, ferrite antennas, nickel ferrite, magnetic dielectrics, powder metallurgy.

PAGES: 118
BIG AREA: Engenharias
AREA: Engenharia Elétrica
SUBÁREA: Telecomunicações
SPECIALTY: Teoria Eletromagnetica, Microondas, Propagação de Ondas, Antenas
SUMMARY:

Due the need to develop new wireless technologies, the researches involving communication devices has become intense, mainly in characteristics like device miniaturization and reconfigurability. With this objective, this work presents a proposal for the development of ferrimagnetic compounds aiming their application in wireless communication devices. The project was performed starting at the nickel ferrite (NiFe2O4) through Sol-Gel modified by ICR technique. A calcination process was applied to eliminate organic compounds from Sol-Gel, as the large particle size production, over 300 nm. The calcination was performed at 1100 °C, for ten hours, with 10 °C/min step. The obtained particles were characterized by SEM, XRD and EDS. Magnetic behavior (hysteresis loop) was also obtained, as complex electric permittivity parameter. All performed morphological characterization were applied in a study of Sol-Gel process efficiency, according to nitrate concentration on chitosan matrix. The nitrate concentration was modified to verify which concentration promote better process efficiency, so that 120 g/L concentration could be verified as the more suitable for a high-quality product. Posteriorly, one of the proposed devices was manufactured: ferrite powder encapsulated with low permittivity wood material, aiming FRA application. Electric characterization was performed in all four types of applied woods. Reflection coefficient was determined and discussed. Then, ferrite bulk materials were manufactured using a 15-ton uniaxial press with propanone binding agent, followed by heating process before sintering. This process was performed with same temperature parameters of the powder production, aiming to not change microscopical characteristics. Electric characterization of ferrite bulk was performed and its application as microstrip patch antenna substrate and FRA was verified. Magnetic permeability was estimated based on previous papers characterization of NiFe2O4 powder. With electric characterization, simulations of FRA, with three different types of excitation, and proposed antennas was performed by HFSS software, using FEM method and the reflection coefficient was experimentally determined to validate the simulations. The experimental results presented good agreement with all performed process of production and characterization, reaching a 0.82% error in resonance frequency based on simulated results. The nickel ferrite potential as FRA and microstrip patch antenna is evidenced along the results discussion, being possible to expand the applications possibilities in other electrical engineering fields.

BANKING MEMBERS:
Presidente - 6345784 - ADAILDO GOMES D ASSUNCAO
Interno - 349732 - LAERCIO MARTINS DE MENDONCA
Interno - 3921178 - VALDEMIR PRAXEDES DA SILVA NETO
Externo ao Programa - 338292 - JOAO BOSCO LUCENA DE OLIVEIRA
Externo à Instituição - IDALMIR DE SOUZA QUEIROZ JÚNIOR - UFERSA
Externo à Instituição - JOABSON NOGUEIRA DE CARVALHO - IFPB