High microwave dielectric performance and applications in antenna of novel Li ₇ La ₃ Zr ₂ O ₁₂ ceramics

This study pioneers the cross‐disciplinary application of garnet‐type solid‐state electrolyte Li 7 La 3 Zr 2 O 12 (LLZO) in microwave dielectric ceramics. LLZO was synthesized via solid‐state reaction, achieving optimized microwave dielectric properties at 900°C: ε r = 8.13, Q × f = 31 735 GHz, τ f = −44.3 ppm/°C. Direct cofiring experiments with Ag electrodes validated its compatibility with low‐temperature cofired ceramic (LTCC). X‐ray diffractometer (XRD)/scanning electron microscope (SEM)–energy‐dispersive X‐ray spectroscopy (EDS) confirmed interfacial stability and chemical inertness, overriding standalone thermal expansion parameter considerations. A Beidou antenna prototype on LLZO substrates demonstrated 59.2 MHz bandwidth at 1.57 GHz with 4.33 dBi gain and >97% radiation efficiency. By synergizing low‐loss microwave response with inherent Li⁺ conductivity and thermal robustness, LLZO emerges as a multifunctional platform for integrated energy‐communication systems. It enables future designs of LTCC based self‐powered modules and real‐time structural health monitoring devices. This work bridges solid‐state electrolytes and microwave ceramics, offering a paradigm for material innovation in fifth‐generation (5G)/sixth‐generation (6G) networks and intelligent electronics.