Temperature-stable Li4Ti3O8 composite microwave dielectric ceramics and their applications in dielectric resonator antennas

Li4Ti3O8 composite ceramics were synthesized via the solid-state reaction method. The microwave dielectric properties of these ceramics and their potential applications in dielectric resonator antennas were analyzed in detail. The relative density predominantly influenced the epsilon(r) and Q x f of Li4Ti3O8 ceramics. The optimal microwave dielectric properties (epsilon(r) = 26.7, Q x f = 66 020 GHz, and tau(f) = -3.3 ppm degrees C-1) were achieved through sintering at 1160 degrees C. There is a minimal change of epsilon(r) of Li4Ti3O8 ceramics over a wide temperature range (-100 degrees C to 100 degrees C), indicating excellent stability. A cylindrical DRA prototype fabricated from Li4Ti3O8 resonates at 6.45 GHz (S-11 < -10 dB) with a maximum radiation efficiency exceeding 92.6%. In conclusion, the Li4Ti3O8 material is a viable candidate for 5/6G applications owing to its low loss and temperature stability advantages.