Low loss Co2Z (Ba3Co2Fe24O41)–glass composite for gigahertz antenna application

Abstract

Low magnetic and dielectric loss Co2Z (Ba3Co2Fe24O41)–glass composite in the frequency range of 1–3 GHz is reported. Co2Z–glass composite was prepared by firing a mixture of 40 h shake-milled Co2Z hexaferrite powder and borosilicate glass at 950 °C for 1 h. The real part of permeability decreased slightly from 2.29 to 1.96 at 2.4 GHz as the glass content increased from 0 to 4 wt. %, but magnetic loss decreased less than 0.02. On the other hand, the real part of permittivity was 7.29 at 0 wt. % and 7.28 at 4 wt. % glass and dielectric loss was less than 0.01 at 2.4 GHz. The 3D peak gain of Co2Z–glass composite chip antenna was measured to be 3.32 dBi at 2.35 GHz. These results imply that the Co2Z–glass composite is an underpinning magnetodielectric material for gigahertz antenna applications.

Magnetic and electrical properties of Z-type hexaferrites sintered in different atmospheres

“…Unfortunately, Co 2 Z tends to be quite lossy due to its high fabrication temperature [3], limiting its applicability in antenna. Attempts have already been made to reduce magnetic and dielectric losses by Jaejin Lee et al [7] and Qi Xia et al [8], by doping or compositing with other materials. In this work, we tried to reduce the loss of Co 2 Z by changing the sintering atmosphere.…”

“…Recently, with the development of wireless systems, hexaferrites have received renewed attention for their potential applications as low-loss antenna substrate materials [1][2][3][4][5][6][7][8][9][10].…”

Hexaferrite slant and slot MIMO antenna element for mobile devices

“…Nikitin et al proposed a theory and a measurement methodology for determining the RFID tag radar cross section (RCS) [8]. The study is completed considering the differential RCS, especially important for practical implementation in noisy environment and long read distance applications [9]. The (delta) RCS is today know as a very critical parameter that governs the tag performance, and also, influences both the reading distance as well as the sensitivity of tag.…”

Introduction of NiZn-Ferrite Into Co$_{2}$Z-Ferrite and Effects on the Magnetic and Dielectric Properties

“…In the practical high-frequency applications, high initial permeability, proper dielectric constant, low magnetic and dielectric loss are required for the Co Z ferrite. Many investigations have been carried out to meet the requirements, such as ions substitution and adding some nonmagnetic substances [4]- [8]. Most of the nonmagnetic additives are characterized by high resistivity and good chemical stability.…”