@PhDThesis{Tenório:2023:ObCaCe,
author = "Ten{\'o}rio, Pl{\'{\i}}nio Ivo Gama",
title = "Obten{\c{c}}{\~a}o e caracteriza{\c{c}}{\~a}o de
cer{\^a}micas CaCu3Ti4O12 e avalia{\c{c}}{\~a}o de suas
propriedades para aplica{\c{c}}{\~a}o como material absorvedor
de radia{\c{c}}{\~a}o eletromagn{\'e}tica",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2023",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2023-02-28",
keywords = "MARE, CCTO, absorvedor de micro-ondas, absorvedores multicamadas,
RAM, microwave, CCTO, microwave absorber.",
abstract = "O aumento na demanda de equipamentos eletr{\^o}nicos e de
sistemas de telecomunica{\c{c}}{\~o}es operantes em altas
frequ{\^e}ncias (MHz e GHz) tem tamb{\'e}m aumentado a busca
para solu{\c{c}}{\~o}es para problemas relacionados {\`a}
interfer{\^e}ncia eletromagn{\'e}tica (EMI). Um dos m{\'e}todos
empregado para superar esse desafio {\'e} a
utiliza{\c{c}}{\~a}o de materiais absorvedores de
radia{\c{c}}{\~a}o eletromagn{\'e}tica (MARE), esses materiais
s{\~a}o capazes de blindar e/ou absorver a onda
eletromagn{\'e}tica causadora de interfer{\^e}ncias e s{\~a}o
aplicados em setores como o aeroespacial, aeron{\'a}utico, na
medicina, telecomunica{\c{c}}{\~o}es, militar, entre outros.
Muitos compostos podem ser utilizados para essa
aplica{\c{c}}{\~a}o, entretanto, os comp{\'o}sitos possuem
muitas vantagens, como a possibilidade de controlar as
propriedades diel{\'e}tricas e/ou magn{\'e}ticas do material.
Dessa forma, este trabalho busca desenvolver um comp{\'o}sito de
matriz polim{\'e}rica capaz de absorver a energia da onda
eletromagn{\'e}tica na faixa de frequ{\^e}ncia de 12,4 at{\'e}
18 GHz (banda Ku), com o a maior largura de banda
poss{\'{\i}}vel. Para isso, foram utilizados o titanato de cobre
e c{\'a}lcio (CaCu3Ti4O12), a ferrocarbonila (FC) e a ferrita de
mangan{\^e}s e zinco (Mn0,6Zn0,4Fe2O4) como aditivos. Foram
produzidas amostras para tr{\^e}s tipos de experimentos. O
primeiro de multicamadas, utilizando duas e tr{\^e}s camadas, com
diferentes combina{\c{c}}{\~o}es de material e espessura, o
segundo utilizando a mistura em composi{\c{c}}{\~o}es diferente
do titanato (CCTO) com a ferrocarbonila e o terceiro com aditivos
que passaram por rea{\c{c}}{\~a}o no estado s{\'o}lido. Antes
da fabrica{\c{c}}{\~a}o dos comp{\'o}sitos os aditivos foram
caracterizados por t{\'e}cnicas como: DRX, MEV, Raman e VSM. As
caracteriza{\c{c}}{\~o}es de fase cristalina indicaram uma
{\'u}nica fase nos compostos testados. Foram verificadas
morfologias irregulares para o CCTO e a Ferrita MnZn, enquanto
para FC foi observado o formato esf{\'e}rico. Nos aditivos
produzidos por rea{\c{c}}{\~a}o no estado s{\'o}lido (CCTO+FC)
as medidas estruturais n{\~a}o apresentaram forma{\c{c}}{\~a}o
de novas fases para os compostos produzidos. Contudo, foi
verificado que o tratamento t{\'e}rmico alterou o tamanho do
cristalito da FC e influenciou na ader{\^e}ncia das
part{\'{\i}}culas e forma{\c{c}}{\~a}o de aglomerados de
ferrocarbonila na superf{\'{\i}}cie dos gr{\~a}os de CCTO. As
propriedades eletromagn{\'e}ticas dos comp{\'o}sitos foram
caracterizadas em um analisador de rede vetorial (VNA), na faixa
de frequ{\^e}ncia de 12,4 a 18 GHz (banda Ku). O experimento de
multicamadas utilizou um programa em Phyton para simular a
refletividade de 24 configura{\c{c}}{\~o}es com duas camadas e
108 com tr{\^e}s camadas. As camadas {\'u}nicas tamb{\'e}m
tiveram sua refletividade mensurada. O destaque desse conjunto de
medidas foi para as amostras 2mm FC + 1mm Ferrita MnZn + 2 mm CCTO
e 2mm FC, que obtiveram 3,56 GHz e 3,1 GHz de largura de banda,
respectivamente. As amostras com dois aditivos n{\~a}o
apresentaram resultados atrativos. Entretanto, as amostras
produzidas utilizando as misturas preparadas com 50% em massa de
cada aditivo e aquecidas nas temperaturas de 200 °C e 300 °C
obtiveram resultados com 4,91 GHz (de 13,09 a 18 GHz), ou seja,
mais de 87% da faixa de frequ{\^e}ncia da banda Ku foi absorvida.
ABSTRACT: The increasing demand for electronic devices and
telecommunication systems operating at high frequencies (MHz and
GHz) has also increased the search for solutions to problems
associated with electromagnetic interference (EMI). The radar
absorbing materials (RAM) is one method used to overcome this
challenge. These materials are capable of shielding and/or
absorbing the electromagnetic waves that cause interference. In
general, RAM are present in many areas, such as: aerospace,
medical, telecommunications, military, etc. This application can
use many compounds, but composites have many advantages, such as
the possibility to control the dielectric and/or magnetic
properties of the material. Therefore, the aim of this work is to
develop a polymer matrix composite material capable of absorbing
electromagnetic wave energy in the frequency range of 12.4 to 18
GHz (Ku band) with the larger possible bandwidth. For this, copper
calcium titanate (CaCu3Ti4O12), carbonyl iron (CI) and manganese
zinc ferrite (Mn0.6Zn0.4Fe2O4) were the aditives. For this, copper
calcium titanate (CaCu3Ti4O12), carbonyl iron (CI) and manganese
zinc ferrite (Mn0.6Zn0.4Fe2O4) were the additives. Three types of
experiments were performed. TThe first of multilayers, with two
and three layers, the second used the mixture in different
compositions of titanate (CCTO) with carbonyl iron and the third
with additives that underwent reaction in the solid state. Before
the production of the composites, the additives were characterized
by techniques such as XRD, SEM, Raman and VSM. Structural
characterization indicated a single phase in the tested compounds.
Irregular morphologies were observed in CCTO and Ferrite MnZn,
while is spherical in FC. For the additives prepared by
solid-state reaction (CCTO+FC), the structural measurements
generally did not show the formation of new phases for the
prepared compounds. However, it was demonstrated that the heat
treatment changed the crystallite size of FC and affected the
adhesion of the particles and the formation of carbonyl iron
agglomerates on the surface of the CCTO grains. The
electromagnetic properties of the composites were characterized
using a vector network analyzer (VNA) in the frequency range from
12.4 to 18 GHz (Ku band). For the multilayer experiment, a Python
program was used to simulate the reflectivity of 24 configurations
with two layers and 108 with three layers. Reflectivity was also
measured for single devices. The highlight of this set was the
samples 2mm FC + 1mm Ferrite MnZn + 2mm CCTO and 2mm FC, which
achieved a bandwidth of 3.56 GHz and 3.1 GHz, respectively.
Samples with two additives were not attractive. However, as more
reflected with the prepared mixtures, with 50% of each additive
and with temperatures of 200 °C and 300 °C obtained,8 with 4 GHz
(from 13.09 to 13 GHz), or with 4 GHz (from 13.09 to 13 GHz), or
more than 87 Ku-band frequency was out of range.",
committee = "Mineiro, Sergio Luiz (presidente/orientador) and Baldan, Mauricio
Ribeiro (orientador) and An, Chen Ying and Toledo, Rafael Cardoso
and Silva, Valdirene Aparecida da",
englishtitle = "Characterization of CaCu3Ti4O12 properties and its evaluation for
material absorber of electromagnetic radiation applications",
language = "pt",
pages = "101",
ibi = "8JMKD3MGP3W34T/48L8G9B",
url = "http://urlib.net/ibi/8JMKD3MGP3W34T/48L8G9B",
targetfile = "publicacao.pdf",
urlaccessdate = "2024, Apr. 29"
}