Optimizing the microwave dielectric and mechanical properties of Ca(Pr0.2Nd0.2Sm0.2Eu0.2Y0.2)AlO4 ceramic by high-entropy strategy

In microwave communication, combining a high quality factor ( Q×f ; i.e., low dielectric loss) with a near-zero temperature coefficient of resonant frequency ( τ f ) remains a significant challenge. Here, we propose to enhance the structural stability of the rock-salt and perovskite layers in K 2 NiF 4 -type ceramics by using entropy engineering methods, thereby reducing dielectric loss and improving the temperature stability of the resonant frequency. Novel high-entropy ceramics Ca(Pr 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Y 0.2 )AlO 4 with a K 2 NiF 4 structure have been synthesized via the solid-state reaction method. Excellent microwave dielectric properties with a low permittivity ( ε r ) of 19.4, a Q×f of 105,223 GHz, and a near-zero τ f of −6.23 ppm/°C were obtained at 1400 °C. A significant enhancement in the mechanical properties of Ca(Pr 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Y 0.2 )AlO 4 ceramic was achieved due to the improvement of configuration entropy. Furthermore, a cylindrical dielectric resonator antenna (CDRA) was developed, showcasing a high simulated radiation efficiency of 93.9 % and a gain of 6.66 dBi at the center frequency of 3.25 GHz. This indicates that Ca(Pr 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Y 0.2 )AlO 4 high-entropy ceramic holds promising applications in satellite communication due to its low dielectric loss.