A new additive-free microwave dielectric ceramic system for LTCC applications: (1 − x)CaWO4 − x(Li0.5Sm0.5)WO4

In this work, a novel additive-free microwave dielectric ceramic (MWDC) system of (1 − x)CaWO4−x(Li0.5Sm0.5)WO4 (CW-LSW, 0.12 ≤ x ≤ 0.20) for low temperature co-fired ceramic (LTCC) applications was successfully fabricated by a solid-state reaction route. The sintering temperature and composition effects on the microwave dielectric (MWD) properties, microstructures, and crystalline phases were investigated. The optimal sintering temperatures of the CW-LSW ceramics are ranging from 875 to 950 °C. When sintered at 900 °C for 3 h, the sample of 0.86CW-0.14LSW exhibited excellent MWD properties: εr = 10.76, Q × f = 28,754 GHz, and τf = − 0.54 ppm/°C. Furthermore, it is found that the CW-LSW ceramics are well compatible with Ag electrode during the sintering process. Therefore, the findings suggest that CW-LSW ceramic materials are promising for LTCC applications.