Publication: Tunable rattling effect and microwave dielectric properties in orthorhombic AEu2O4 (A = Sr, Ba) ceramics for dielectric resonator antennas
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Issued Date
2026-01-15
Resource Type
ISSN
09258388
Scopus ID
2-s2.0-105024723683
Journal Title
Journal of Alloys and Compounds
Volume
1050
Rights Holder(s)
SCOPUS
Bibliographic Citation
Journal of Alloys and Compounds Vol.1050 (2026)
Suggested Citation
Zhang S., Tang Y., Zhong Q., Qing P., Pulphol P., Qin Y., Xiang H., Fang L. Tunable rattling effect and microwave dielectric properties in orthorhombic AEu2O4 (A = Sr, Ba) ceramics for dielectric resonator antennas. Journal of Alloys and Compounds Vol.1050 (2026). doi:10.1016/j.jallcom.2025.185602 Retrieved from: https://hdl.handle.net/20.500.14740/55368
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Abstract
The challenges of achieving high efficiency, high frequency, high selectivity, and low delay in dielectric resonator antennas are critical for 5 G/6 G communications. Therefore, adjusting the strength of the rattling effect emerges as a primary factor governing the overall microwave dielectric polarization and loss in these materials. In this work, AEu<inf>2</inf>O<inf>4</inf> (A = Sr, Ba) ceramics with an orthorhombic structure were successfully synthesized by solid-phase sintering method. SrEu<inf>2</inf>O<inf>4</inf> (1475 °C) exhibited the microwave dielectric properties of ε<inf>r</inf> = 20.1, Q×f = 28,963 GHz, and a near-zero τ<inf>f</inf> of −9.9 ppm/°C, while BaEu<inf>2</inf>O<inf>4</inf> (1500 °C) demonstrated relatively lower ε<inf>r</inf> and higher Q×f values of 18.4 and 57,994 GHz, respectively, along with a negative τ<inf>f</inf> of −36.3 ppm/°C. Compared with the measured permittivity ε<inf>r</inf>, the theoretical permittivity ε<inf>r(C-M)</inf> (18.0) of SrEu<inf>2</inf>O<inf>4</inf> is underestimated, which is mainly related to the under-bonding of Sr-O and Eu(2)-O. The strong rattling effect of Sr-O and Eu(2)-O is the main reason for obtaining the near-zero τ<inf>f</inf> value in SrEu<inf>2</inf>O<inf>4</inf>, while the mitigated rattling effect of Eu(1)-O in BaEu<inf>2</inf>O<inf>4</inf> results in an increased Q×f value. Meanwhile, Q×f values correlate with lattice energy, electrical properties, covalent bonding, and structural stability. Moreover, a dielectric resonant antenna was designed and simulated with BaEu<inf>2</inf>O<inf>4</inf> to meet the requirements of satellite communication.