Experimental and numerical investigation of the microwave dielectric properties of the MgTiO₃ ceramic matrix added with CaCu₃Ti₄O₁₂

Abstract

This paper describes an experimental and numerical investigation of the dielectric resonators based on the MgTiO₃ ceramic matrix, which relates to their dielectric properties in microwave. The resonators are compounds of the MgTiO₃ added with 4, 6, 8, 10 and 12 wt% of the CaCu₃Ti₄O₁₂. The manufacturing process of the resonators is based on the solid-state method. The properties of the permittivity and dielectric loss are elucidated using the Hakki and Coleman´s method. The experimental measurements of the dielectric resonators, acting as antennas, provide some results as return loss, gain, efficiency, bandwidth and input impedance. These results are coherent with the numerical investigation. The addition of the perovskite CaCu₃Ti₄O₁₂ in the MgTiO₃ ceramic matrix increased the value of the dielectric constant and it was obtained a higher value of 21.01 for the sample MgTiO₃ added with 12% CaCu₃Ti₄O₁₂. The temperature coefficient of resonant frequency (τ_f) was measured for all the samples and the best value obtained was 9.62 ppm/°C for the sample MgTiO₃ added with 12% CaCu₃Ti₄O₁₂. The material duly proposed, shows to be promising for applications as dielectric antennas and this study point out that it is possible to obtain a dielectric resonator antenna (DRA) with a temperature coefficient of resonant frequency close to zero.

Index Terms
MgTiO₃; CaCu₃Ti₄O₁₂; ceramic; composite; antennas; microwave properties