Magnetic and dielectric properties of Co–Zn nanoferrites for high-frequency miniaturized antennas

The current study aims to determine the optimal ferrite composition for a substrate material with good magneto-dielectric properties and low losses in order to fabricate high-frequency miniaturized antennas. Cobalt–zinc ferrite samples with different concentration of zinc were synthesized using the sol–gel method and polyvinyl alcohol as the chelating agent. The lattice constant obtained through experimentation agrees with the one obtained from the suggested cation distribution and Rietveld refinement, indicating that zinc has entered the tetrahedral sites of the spinel structure. A higher zinc concentration was associated with a lower average grain size, ranging from 96.7 to 62.4 nm. The investigation will examine complex permittivity, complex permeability, dielectric and magnetic loss tangents, and AC conductivity in order to evaluate the effects of frequencies between 1 MHz and 2 GHz. The material with the composition Co0.4Zn0.6Fe2O4 exhibits low AC conductivity (1.28 × 10−6 S/cm), low values of magnetic and dielectric loss tangents (0.047, 0.013) at 100 MHz frequency, and a stable miniaturization factor (n = 4.2) over a broad frequency range of 10 MHz to 1 GHz. The persistent magneto-dielectric behavior and low-loss properties of cobalt–zinc nanoferrite confirm that it is a suitable substrate material for high-frequency antenna design.