The regulation of high-frequency magnetic properties of NiZnCo ferrite for miniaturized antenna application

Abstract

Demand for communication devices with miniaturization and high-frequency capability requires materials with high permeability, matching permittivity, low loss, and high operating frequency. In this study, the micromorphology of NiZnCo ferrites synthesized by the co-precipitation method is regulated by changing the sintering temperature, obtaining a domain structure with a high-performance factor (PF). Specifically, the effect of Co ion content on the static and high-frequency magnetic properties of NiZnCo ferrites is analyzed at a sintering temperature of 800 °C. Results reveal that the value of Snoek limit and the magnetocrystalline anisotropy constant of NiZnCo ferrites increase with Co ion content enhances from 0.2 to 0.5, thereby PF elevates from 34.7 GHz (at the maximum operating frequency f0 = 1.04 GHz) to 48.7 GHz (f0 = 2.25 GHz). PF value of Ni0.31Zn0.19Co0.5Fe1.98O4-δ ferrite is measured to be 48.7 GHz at 2.25 GHz. Furthermore, a planar inverted F antenna (PIFA) is designed using Ni0.31Zn0.19Co0.5Fe1.98O4-δ ferrite. The PIFA exhibits a maximum gain of 3.7 dB and a miniaturization rate of 4.6 %. This study holds significant implications for the development of magneto-dielectric materials for use at 2.0 GHz.