Rational optimizations of high K microwave dielectric ceramic Bi₂(Li_0.5Ta_1.5)O₇ toward LTCC applications

Microwave dielectric ceramics have drawn intensive interests in recent years due to the advanced development in communication area. High-permittivity dielectric ceramics have thus become the highlight owing to dielectric ceramics with high permittivity could meet the demand of electronic components in both stabilization and miniaturization features. Bi₂(Li_0.5Ta_1.5)O₇ shows its great potential among various high-permittivity dielectric ceramics with a suitable permittivity and a considerable quality factor. Based on previous studies, a series of rational optimizations were conducted on Bi₂(Li_0.5Ta_1.5)O₇ to manipulate the temperature coefficient of resonant frequency (TCF) and the sintering temperature for potential Low Temperature Co-fired Ceramic (LTCC) applications. Two distinguished ceramics were obtained, Bi₂(Li_0.5Ta_1.5)O₇–0.03Bi₂O₃ (sintering temperature of 850°C, ε_r ∼ 64.1, Qf ∼ 8510 GHz, TCF—25.3 ppm/°C) and Bi₂[(Li_0.5Ta_1.5)_0.975Ti_0.05]O₇–0.015Bi₂O₃ (sintering temperature of 980°C, ε_r ∼ 66.2, Qf ∼ 10 950 GHz, TCF—8.5 ppm/°C). Dielectric resonator antenna (DRA) simulation was subsequently conducted and proved the ceramics holding excellent potential for microwave applications.