Hexagonal SrFe12O19: Oxide Method Synthesis, Optical and Magnetic Properties and 5G Circulator Applications

High-purity SrFe12O19 ferrite was synthesized by an oxide method using Fe2O3 that was prepared through a hydrothermal method and Sr(NO3)(2) as the source material. The products sintered at 900-1200 degrees C were composed of SrFe12O19 and Fe2O3, and the pure hexagonal SrFe12O19 ferrite was found at 1250 degrees C. The microstructure of the SrFe12O19 ferrite showed that the particle size increased with the increase in sintering temperature, which is consistent with the trend in crystallite size calculated by x-ray powder diffraction (XRD). The particles were transformed from an approximately spherical shape to an irregular shape. The color of the SrFe12O19 ferrite changed from brown at 900 degrees C to black at 1250 degrees C. The optical bandgap (E-g) decreased with the increase in sintering temperature. The magnetic properties showed that the saturation magnetization and remanent magnetization of the SrFe12O19 ferrite increased with the increase in sintering temperature, while the squareness ratio (SQR) first increased first and then decreased with the increase in sintering temperature. The saturation magnetization, remanent magnetization, and SQR of pure SrFe12O19 were 49.47 emu g(-1), 33.32 emu g(-1), and 0.67, respectively. The microstrip line circulator was simulated by high-frequency electromagnetic field simulation software based on the testing of the magnetic properties of the SrFe12O19 ferrite and the Bosma first and second ring conditions, and an ideal model was obtained. The model showed a good ring effect in the range of the K-band (18-27 GHz), center frequency of 25 GHz, sin psi = 0.3, and port isolation of about -30 dB. This research will aid in the development of lightweight, miniaturized, and integrated circulators, and has broad application potential in the field of communications.