Magnetodielectric Bi–Co–Ti substituted M-type hexaferrite with high and matching permeability and permittivity in very high frequency

This paper demonstrated the magnetic and dielectric properties of Bi–Co–Ti substituted M-type hexaferrite prepared by solid-state reaction method. With the aid of Bi substitution, the sample can be sintered well at 950 °C and be of a high density of 4.96 g/cm3. The sample shows matching permeability and permittivity with equal values as high as 24 within 10–200 MHz, which leads to a high refractive index of 24 and perfect impedance matching to free space. The impedance matching material with low magnetic and dielectric loss is a promising candidate as the substrate of very high frequency (VHF) antennas toward miniaturization.