BaCu(B₂O₅) is a typical microwave dielectric ceramic (MDC) with a low sintering temperature, but it exhibits a large negative temperature coefficient of resonant-frequency (τ_f) which makes it difficult to use in wireless communications. We employ TiO₂ to improve its temperature-stability of resonant-frequency, and reveal the effects of TiO₂ on the densification and the microwave dielectric properties of BaCu(B₂O₅). Here we show that BaCu(B₂O₅) can be well-sintered at 825 °C with proper TiO₂ additions; we find that the TiO₂ grains homogeneously distribute in the boundaries of BaCu(B₂O₅) grains, resulting in the τ_f compensation of BaCu(B₂O₅). Enhanced temperature-stability of resonant-frequency can be achieved by increasing the content of TiO₂ properly. A novel temperature-stable (1-x)BaCu(B₂O₅)–xTiO₂ (x = 0.20) MDC (τ_f =−0.8 ± 3.0 ppm/°C, ε_r = 8.8 ± 0.36, Q×f = 28,612 ± 1170 GHz) is obtained using some low-cost raw materials. Our results provide the underlying insights needed to guide the design of temperature-stable MDCs for wireless communication applications.

BaCu（B ₂ O ₅）是一种典型的烧结温度低的微波介电陶瓷（MDC），但是它具有较大的谐振频率负温度系数（_τf），这使其难以用于无线通信中。我们采用TiO ₂来提高其共振频率的温度稳定性，并揭示TiO ₂对BaCu（B ₂ O ₅）的致密化和微波介电性能的影响。在这里，我们表明，添加适当的TiO ₂可以在825°C下很好地烧结BaCu（B ₂ O ₅）。我们发现TiO ₂晶粒均匀地分布在BaCu（B ₂ O ₅）晶粒的边界中，从而导致BaCu（B ₂ O ₅）的_τf补偿。通过适当地增加TiO ₂的含量，可以提高共振频率的温度稳定性。一种新型的温度稳定的（1- x）BaCu（B ₂ O ₅）– x TiO ₂（x  = 0.20）MDC（_τf = -0.8±3.0 ppm /°C，_εr  = 8.8±0.36，Q× f = 28,612±1170 GHz）是使用某些低成本原材料获得的。我们的结果提供了指导无线通信应用中温度稳定的MDC设计所需的基础见解。