Investigação das Propriedades Elétricas e Térmicas dos Titanos, La2Ti2O7 e BiCu3Ti3FeO12, para Aplicações em Engenharia de Micro-ondas

Abstract

In this work we developed and analyzed the structural and dielectric properties of two ceramic phases LTO(La2TI2O7) and BCTFO(BiCu3Ti3FeO12). The LTO ceramic was bulk added titanium oxide in proportions of 1, 3 and 5% and BCTFO ceramic was bulk added iron oxide in proportions of 20, 40 and 60%. For the production of samples of the two ceramic series, the solid state reaction method was used. Then, X-ray diffraction analysis was performed to characterize the structures and composition of the samples. After, where we confirmed the formation of the BCTFO and LTO phases, we moved on to the preparation of the parts. In this step, the samples were pressed in the form of cylinders and sintered, the LTO samples at 1100oC and the BCTFO samples at 900oC. In the next step, the dielectric characterization was performed both in the radiofrequency (RF) and microwave (MW) region. With the results we present a possible application in RF and MW devices. In these studies carried out in RF and MW, we aim to develop ceramic dielectric components with high dielectric constant, low dielectric losses, thermal stability, with good bandwidth, gain and efficiency. In the MW range, we verified the variation of the dielectric constant and the tangent of losses of the two ceramic phases with the addition of the oxides. Still in the MW region, we measured the resonance frequency temperature coefficient which showed values close to zero for the LTO series samples added 3% and 5% TiO2 by mass. In the BCTFO matrix we were able to predict a good thermal stability for the mass additions of 63.63% and 75.26% of Fe2O3. We end with Numerical Simulations. These showed a good approximation between the measured and simulated values. From these we can see that the two ceramic series produced can be useful for application in devices that operate both in the RF region and in MW.