High-entropy enhanced microwave dielectric performance

Microwave dielectric ceramics with excellent dielectric properties are essential for microwave devices. However, developing microwave dielectric ceramics with optimal permittivity (ε_r), a high quality factor (Q×f), and a near-zero temperature coefficient of resonant frequency (τ_f) remains a significant challenge. We propose a high-entropy design with local disordered ionic displacement in spinel-structural ceramics. This strategy stabilizes the phase structure by lowering the Gibbs free energy and enhances the performance of ceramics through lattice distortion, sluggish diffusion kinetics, and multi-component synergy. Benefiting from the synergistic effect, we achieved excellent properties in high-entropy spinel ceramics, including a ε_r of 10.33, a high Q×f of 120,545 GHz, a near-zero τ_f of −10.7 ppm/°C, as well as a Vickers hardness of 9.98 GPa and a flexural strength of 134.1 MPa. Furthermore, the resonant antenna designed based on high-entropy ceramics satisfies the application requirements for 5G/6G communications. This work demonstrates that the high-entropy strategy is an advanced method for the development of high-performance microwave dielectric ceramics and antennas.