High-entropy gallium-based garnet microwave dielectric ceramics with low loss for C-band dielectric resonator antenna application

Abstract

In this work, (Y0.5 Nd0.5 Sm0.5 Eu0.5 Ho0.5 Yb0.5 )Ga5 O12 high-entropy ceramic with a cubic garnet structure was designed and synthesized via a solid-state reaction method. Through the high-entropy regulation of the oxygen dodecahedron, the bond strength increases, the cation's bond valence approaches the ideal value, and the structural stability improves, thereby promoting the Q × f value. Low dielectric loss (Q × f = 130,100 GHz) was obtained in the high-entropy ceramic (Y0.5 Nd0.5 Sm0.5 Eu0.5 Ho0.5 Yb0.5 )Ga5 O12 , which exhibited a low relative permittivity (εr ) of 12.36, a negative temperature coefficient of resonant frequency (τf ) of −66.37 ppm/°C, and a high flexural strength of 229.68 MPa. Furthermore, a cylindrical dielectric resonator antenna (CDRA) was designed featuring high radiation efficiency (>90 %) and stable gain (5.91–5.97 dBi) within a 255 MHz bandwidth, showing promising application prospects in the C-band. This work indicates that the high-entropy strategy is feasible for the design of high-performance microwave dielectric ceramics.