Investigation of Zn2+-Mn3+ co-substituted Z-type hexaferrite for patch antenna application

Abstract

As a substrate material for microstrip patch antennas, enhancing the high-frequency magneto-dielectric properties of ferrite is a crucial research challenge. Herein, a series of Zn²⁺-Mn³⁺ co-substituted Ba_1.5Sr_1.5Co_2-xZn_xMn_yFe_23-yO_41-δ hexaferrites is reported. The phase composition, crystal structure, microstructure, ion valence and magneto-dielectric properties of the samples are systematically investigated. The study reveals that the hexaferrite with x = y = 0.4 has superior magneto-dielectric properties due to its single phase, highly compact, enhanced permeability and dielectric constant, and low magnetic and dielectric losses. Meanwhile, its miniaturization factor (n) exceeds 17 while the normalization constant approaches 1, representing the excellent high-frequency magneto-dielectric properties. Finally, a rectangular microstrip patch antenna is designed and simulated using the optimized hexaferrite. It demonstrates an operational frequency of 0.8 GHz, small size, and excellent radiation performance with $S_{11}$ = -19.43 dB, BW = 346 MHz, and VSWR = 1.86.