Preparation of phase-pure MgTiO3 microwave dielectric ceramics for GPS antenna application

Abstract

MgTiO₃ is an important dielectric material used in microwave applications. However, it is difficult to preserve its phase purity during calcination and sintering, limiting its applications and demanding the addition of other materials. Herein, we report the evaluation of structural and microwave dielectric properties of phase-pure MgTiO₃ ceramics with respect to their calcination temperature. MgTiO₃ powder was synthesized through a solid-state method by preprocessing its precursors. The ball-milled precursor powder mixture was calcined at different temperatures. Structural properties of the calcined powders were studied through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy analyses. The surface morphology and particle size of MgTiO₃ were observed using optical microscopy and field emission scanning electron microscopy (FESEM) techniques. The calcined powders were then sintered at 1300–1550 °C. The density and dielectric properties of sintered MgTiO₃ pellets were compared with respect to the calcination temperature. Single-phase MgTiO₃ ceramic without additives calcined at 1000 °C and sintered at 1500 °C for 4 h exhibited excellent dielectric constant (ε_r), quality factor (Q × f) and temperature coefficient of resonant frequency (τ_f) values of 18.2, 103 241 and −45.23 ppm per °C, respectively. Furthermore, the design, simulation and fabrication of a GPS patch antenna prototype using the optimized MgTiO₃ ceramic powder revealed its applicability for use in the L1 microwave band.