Abstract Two novel tungstate ceramics with a nominal composition of Ca3Ln2W2O12 (Ln = La, Sm) were prepared via standard solid-state reaction methods. According to X-ray diffraction patterns, both ceramics crystallized in hexagonal crystal systems with a space group of R 3 ¯ m (No. 166). The vibrational modes of the Raman spectra were identified, and the evolutions of the wavenumber and the full width at half maximum (FWHM) were analyzed. The optimum microwave dielectric properties with er = 18.7, Qf = 50,500 GHz, and τf =–90 ppm/oC were realized in Ca3La2W2O12 ceramics, while moderate Qf values were obtained in the Sm composition (er = 19.5, Qf = 15,700 GHz, and τf =–95 ppm/oC). The discrepancy in the Qf values was associated with the broader FWHM of Raman spectra and smaller grain sizes. Infrared reflectivity (IR) spectra were also used to determine the intrinsic dielectric loss, where more damped phonon parameters were also identified in Ca3Sm2W2O12 ceramics.

中文翻译：

---

两种新型 Ca3Ln2W2O12 (Ln = La, Sm) 钨酸盐陶瓷的振动光谱和微波介电性能

摘要 通过标准固相反应方法制备了两种标称组成为 Ca3Ln2W2O12 (Ln = La, Sm) 的新型钨酸盐陶瓷。根据 X 射线衍射图，两种陶瓷均以六方晶系结晶，空间群为 R 3 ¯ m (No. 166)。识别了拉曼光谱的振动模式，并分析了波数和半峰全宽（FWHM）的演变。在 Ca3La2W2O12 陶瓷中实现了 er = 18.7、Qf = 50,500 GHz 和 τf =–90 ppm/oC 的最佳微波介电性能，而在 Sm 组合物中获得了适中的 Qf 值（er = 19.5，Qf = 15,700 GHz，和τf =–95 ppm/oC）。Qf 值的差异与较宽的拉曼光谱 FWHM 和较小的晶粒尺寸有关。