Propriedades dielétricas do compósito (La2Zr2O7) x:(La2Ti2O7)1-x em rf e micro-ondas

Abstract

Composites, materials formed by combining two or more distinct constituents, can be employed in the design of novel dielectric resonators with applicability in dielectric resonator antennas (DRAs). With the rapid development of telecommunication technologies, particularly 5G, satellites, wireless communication devices, and GPS (Global Positioning System), there is a growing demand for the improvement and development of electronic devices based on electroceramics for microwave (MW) and radiofrequency (RF) emission and reception systems. This work investigates the use of La2Zr2O7 (LZO), La2Ti2O7 (LTO), and their composites, ((La2Zr2O7) x: (La2Ti2O7)1-x where x = 0.25, 0.50, 0.75) as dielectric resonator antennas (DRAs) operating in the MW and RF ranges. The materials were synthesized by the solid-state reaction method and characterized using X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). Subsequently, their dielectric properties were studied in the RF range under varying temperatures by impedance spectroscopy (IS), as well as in the MW range. The composites exhibited dielectric constant (εr) values between 22 and 43. Regarding the temperature coefficient of resonant frequency (τf), values ranged from −14 to 33 ppm·°C⁻¹. The addition of LZO into the LTO matrix induced significant changes in the electrical and dielectric properties. Both pure phases and composite samples exhibited thermally activated dielectric relaxation processes at high frequencies and temperatures, with activation energies depending on the LZO content.