Alta estabilidade térmica da matriz Li2TiO3 com adições de Al2O3 nas regiões de radiofrequência e micro-ondas.

Abstract

In recent years, technological development in the area of ceramic materials has attracted the attention of the scientific community due to applications in microwave and radiofrequency (RF) devices. In microwave applications, in general, looking for materials with high dielectric permittivity (εr), low dielectric loss (tanδ), good thermic stability and low cost. This work aims to characterize the ceramics of lithium titanate (Li2TiO3) with addition of 5%; 10%; 15% and 20% by weight of aluminum oxide (Al2O3), verifying which modifications occur in the dielectric properties of the material. The ceramics were produced by the solid-state reaction method using a planetary mill and post-grinding calcination. The structural and morphological characterization was performed using X-Ray Diffraction (XRD) techniques, Raman Spectroscopy and Scanning Electron Microscopy (SEM). Experiments were performed to evaluate the behavior of RF and microwave samples. Finally, the material was tested as a Dielectric Resonator Antenna (DRA), and the results obtained were simulated through the HFSS software. The characteristics of DRA Li2TiO3 are 3.91 dBi of gain and 70.58% of irradiation efficiency. The ARD formed from 5% Al2O3 obtained a gain of 4.26 dBi with efficiency of 74.23%, and also the temperature coefficient of the resonance frequency near zero (-0.58 ppm/°C), showing the potential of this material for microwave circuits that require thermal stability.