Dielectric ceramics are essential components in communication systems that operate within the microwave frequency range. In high-density packages, dielectric substrates ceramics must possess high thermal conductivity to efficiently dissipate heat. However, achieving adequate thermal conductivity (κ) in ceramics sintered at low temperatures is challenging. In this study, we employed the cold sintering process (CSP) to fabricate Li2MoO4-x%Al2O3 (0≤x ≤ 80, in volume) ceramics under 200 MPa pressure at 150 °C. The Li2MoO440%Al2O3 composite exhibited significantly enhanced κ of 5.4 W·m−1·K−1, an 80% increase compared to pure Li2MoO4 ceramic with κ of 3 W·m−1·K−1. At 40% Al2O3 content, the Li2MoO4Al2O3 ceramic demonstrated notable microwave properties (ε ∼ 6.67, Q×f ∼ 17,846 GHz, τf ∼ −105 × 10−6 °C-1). Additionally, simulation of a microstrip patch antenna for 5 GHz applications using Li2MoO420%Al2O3 ceramic as dielectric substrate via Finite Element Simulation software showed excellent performance, with radiation efficiency exceeding 99% and low return loss (S11 < −30 dB) at both 4.9 GHz and 28.0 GHz center frequencies. These findings underscore the suitability of Li2MoO4Al2O3 ceramics for microwave dielectric substrate.

中文翻译：

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冷烧结Li2MoO4[sbnd]Al2O3陶瓷的结构、热和微波介电性能


介电陶瓷是在微波频率范围内工作的通信系统中的重要元件。在高密度封装中，介电基板陶瓷必须具有高导热性才能有效散热。然而，在低温烧结的陶瓷中实现足够的导热系数 （κ） 具有挑战性。在本研究中，我们采用冷烧结工艺 （CSP） 在 200 MPa 压力下、150 °C 下制备了 Li2MoO4-x%Al2O3 （0≤x ≤ 80，体积）陶瓷。 Li2MoO440%Al2O3复合材料的κ显著增强，为5.4 W·m−1·K−1，与 κ 为 3 W·m−1·K−1 的。在 Al2O3 含量为 40% 时，Li2MoO4Al2O3 陶瓷表现出显着的微波性能（ε ∼ 6.67，Q×f ∼ 17,846 GHz，τf ∼ −105 × 10−6 °C-1）。此外，通过有限元仿真软件对使用 Li2MoO420%Al2O3 陶瓷作为介电基板的 5 GHz 应用微带贴片天线进行仿真，在 4.9 GHz 和 28.0 GHz 中心频率下均表现出优异的性能，辐射效率超过 99%，回波损耗低 （S11 < −30 dB）。这些发现强调了 Li2MoO4Al2O3 陶瓷对微波介电衬底的适用性。