High-frequency magnetic properties of modified Cu–Ni 18H ferrites with low magnetic loss up to 6 GHz for 5G communications

Rapidly developing fifth-generation (5G) communications urgently require a ferrite material with high permeability and low magnetic loss in frequency bands up to 6 GHz. However, none of the present magnetic materials are capable of meeting the requirements of 5G communications because their magnetic properties deteriorate drastically when approaching GHz frequencies. Herein, we report the high-frequency magnetic properties of the modified Ba5Cu2-xNixTi3Fe12O31 (Cu–Ni 18H) ferrites, achieving a relatively high permeability of 1.6 and a low magnetic loss of 0.05 at 6 GHz, which is much better than previous reports. Such excellent performance is attributed to the expanded mono-domain critical size and reduced damping of magnetic moment precession. Moreover, deploying Cu–Ni 18H ferrites as a substrate on a patch antenna working at 6 GHz can reduce the antenna dimensions to 35% of traditional commercial materials. The present work provides a proven and promising candidate material for 5G communications and expands the research landscape for the high-frequency magnetic properties of microwave ferrites.