High Permeability Loss Study Of The Hexagonal Ferrite Materials

In this paper, the electromagnetic and absorption properties of polycrystalline hexagonal ferrites, Ba(Zn_1-xCo_x)₂Fe₁₆O₂₇ (W-type) and Ba₃(Zn_1-xCo_x)₂Fe₍24_O41 (Z-type) have been investigated. The samples were prepared by the usual ceramic sintering, and the parameters such as complex permeability μr,complex permittivity εr and reflection loss R(dB) were tested, and some good results were obtained. 1. It was proved that μr of Ba (Zn_1-xCo_x)₂Fe₁₆O₂₇ is the max and the frequency is the least. when x=0.30 and the sintering temperature is 1300℃. 2. Effects of Nd₂O₃ and BST additive on the W-type ferrite was studied. With the increasing of Nd₂O₃ content, μrof W-type ferrite decreased. But with the increasing of BST content, μr,εrof W-type ferrite increase. 3. It was proved that μr of Ba₃(Zn_xCo_1-x)₂Fe₂₄O₄₁ is the max and the frequency is the least. when x=0.7 and the sintering temperature is 1280℃. 4. Effects of Nd₂O₃ additive on the composite Z-type hexaferrite was studied. It was proved that μrof Z-type ferrite increased with the increasing of x. 5. Effects of Nd₂O₃ or Nb₂O₅ additive on the Z-type ferrite was studied. With the increasing of Nd₂O₃ or Nb₂O₅content, μr,εrof Z-type ferrite increase. 6. According to results of the calculated reflection loss(dB), the absorption peak shifted to a lower frequency with increasing the thickness, the tested curve of R(dB) coincided with the calculated R(dB), which means that the calculated reflection loss(dB) was right. In the rang of 8～12GHz, the R(dB) of W-type ferrite doping BST was above 8dB lower than W-type ferrite without BST with the same thickness of 2.5mm, which provides a new approach to improve the absorption properties in the rang. This material has a bright application future in the civilian and military field. 7. according to comparing the simulation result and the real testing result, the simulation results is feasible and accurate.