Dense microwave dielectric ceramics of Sr_1–xCa_xTm₂O₄ (x = 0.025–0.300) were fabricated via the conventional solid-state reaction method. Systematical investigations on the impact of Ca²⁺ on their microstructures, sintering behaviors, and microwave dielectric properties were detailly conducted. The combined XRD data and subsequent refinement demonstrated that all samples exhibited structural conformity with SrTm₂O₄ and belonged to Pnam space group. Calculations were executed to illustrate the evolution of performance-related chemical bonding parameters associated with Ca²⁺ on the basis of the PVL theory. High density, lattice energy and narrow full width at half maximum of Raman modes contribute to a performance boost of around 14%. Excellent dielectric properties of Sr_0.95Ca_0.05Tm₂O₄, including relative permittivity of 15.97, quality factor of 47,142 GHz, and temperature coefficient of resonant frequency of –24.65×10⁻⁶ °C^–1. Furthermore, Sr_0.95Ca_0.05Tm₂O₄ ceramics were designed as rectangular dielectric resonator antennas with 388 MHz bandwidth at the center frequency of 6.525 GHz, along with high simulated radiation efficiency (≥ 90%) and realized gain (5.80–6.47 dBi), which suggests their considerable potential in 5G communication applications.

中文翻译：

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新型 Ca掺杂 Sr1–xCaxTm2O4 （x=0.025–0.300） 陶瓷的晶体结构和化学键特性对微波性能的影响研究


通过常规的固态反应方法制备了 Sr _1-xCa_xTm₂O₄ （x = 0.025-0.300） 的致密微波介电陶瓷。详细研究了 Ca²⁺ 对其微观结构、烧结行为和微波介电性能的影响。结合 XRD 数据和随后的改进表明，所有样品都表现出与 SrTm₂O₄ 的结构一致性，属于 Pnam 空间群。在 PVL 理论的基础上，进行了计算以说明与 Ca²⁺ 相关的性能相关化学键的演变。高密度、晶格能量和拉曼模式半峰的窄全宽有助于将性能提高约 14%。Sr_0.95Ca_0.05Tm₂O₄ 的优异介电性能，包括 15.97 的相对介电常数、47,142 GHz 的品质因数和 –24.65×10⁻⁶ °C^–1 的谐振频率温度系数。此外，Sr_0.95Ca_0.05Tm₂O₄ 陶瓷被设计为矩形介质谐振器天线，在 6.525 GHz 的中心频率下具有 388 MHz 带宽，具有高模拟辐射效率 （≥ 90%） 和实际增益 （5.80–6.47 dBi），这表明它们在 5G 通信应用中具有相当大的潜力。