C-band dielectric resonator antenna with novel ultralow tanδ and temperature stabilized LaTmO3 microwave dielectric ceramics

Currently, research on A 3+ B 3+ O 3 - type microwave dielectric ceramics is scarce. To address these challenges, a novel perovskite - type LaTmO 3 ceramic with a single phase orthorhombic structure (space group Pnma (62)) was synthesized via the solid state reaction method at 1450–1575 °C. Furthermore, SEM was employed to observe the microstructure of the sample, and Raman spectroscopy was utilized to analyze the impact of lattice vibrations on dielectric loss. Additionally, calculations based on the complex chemical bond theory revealed that the values of the εᵣ , Q×f , and τ f were influenced by bond ionicity, lattice energy, and bond energy, respectively. The LaTmO 3 ceramic sintered at 1525 °C demonstrated optimal microwave dielectric properties: Q×f  = 179,601 ± 9579 GHz (at 8.4 GHz), εᵣ  = 27.8 ± 0.18, and τ f  = +9.8 ± 1.5 ppm/°C. Moreover, HFSS simulations demonstrated the applicability of LaTmO 3 in dielectric resonator antennas, achieving >90 % radiation efficiency, about 5.5 dBi gain, and 130 MHz bandwidth at 4.7 GHz, highlighting its potential for 5G oriented components.