High-Frequency Magnetic And Wave-Absorbing Properties Of YIG Ferrite And W-Type Ferrite

With the development of electronic communication equipment,wave-absorbing materials are used in the field of electromagnetic pollution caused by civil communication and military radar stealth to achieve the purpose of shielding electromagnetic interference and avoiding radar detection.In these applications,the-10 d B absorption bandwidth at specific frequencies is particularly important.Good absorption performance of the material,not only should have the advantages of strong absorption,wide absorption bandwidth,but also to meet the practical needs of the premise of its absorbers thinner thickness.It is difficult to have a wider bandwidth in metallic magnetic materials because of their large dielectric constants,which do not easily achieve impedance matching.In order to solve the above technical problems,this paper uses Sc-doped YIG ferrite and W-type barium ferrite as the research objects to prepare and conduct an in-depth study of their wave absorption properties.For the Sc-doped YIG ferrite,the crystal structure,microscopic morphology,electromagnetic parameters and static magnetism are characterized respectively,and the wave absorbing performance is found to have potential applications in the P-band.The variation in the absorber thickness with frequency was also calculated based on the electromagnetic parameters using theλ/4 interference phased extinction mechanism and the magnetic loss mechanism,respectively.It is found that the theoretical thickness obtained by both mechanisms deviates from the actual thickness,and the reflection loss peak formed by theλ/4interferometric phase extinction mechanism is obtained at 211 MHz using the phase relationship of the interface reflection,and the reflection loss peaks formed by both mechanisms are further derived.The absorbing performance in the range of 1 to 1000 MHz is designed by electromagnetic parameters,and the absorption bandwidth is discussed according to the interfacial reflection model,and the theoretical calculation results match with the measured results.For W-type barium ferrite,the effects of Zn-doping on crystal structure,microscopic morphology,electromagnetic parameters and static magnetism are investigated and found to be potentially useful in both X and Ku bands.The W-type ferrites in Ba Co_1.6Zn_0.4Fe₁₆O₂₇and Ba Co_1.4Zn_0.6Fe₁₆O₂₇ basically cover X-band（8-12 GHz）and Ku-band（12-18 GHz）when the absorber thickness is 1.6 mm.After that,the effect of the W-type ferrite and PU complex on the material properties was investigated,and the electromagnetic parameters revealed that the permeability became higher and the dielectric constant increased,and the absorbing properties were derived from the electromagnetic parameters,and the thickness and bandwidth range of the absorbers were found to be significantly increased.Ball-milled 3 h Ba Co_1.6Zn_0.4Fe₁₆O₂₇/PU-60%at 1.3 mm with a bandwidth of 4.83 GHz（7.88-12.71 GHz）and full X-band coverage.The ball-milled 6 h Ba Co_1.8Zn_0.2Fe₁₆O₂₇/PU-60%absorber with a thickness of 1.5 mm has a bandwidth of 7.35 GHz（8.00～15.35 GHz）with full coverage in the X-band,and a thickness of 1.2 mm has a bandwidth of 7.75 GHz（10.25～18 GHz）with full coverage in the Ku-band.Finally,the effect of mixed Bi₂O₃ or Bi₂O₃ and BaTi O₃ on its microscopic morphology,electromagnetic parameters and static magnetism is explored and the wave absorption performance is found to be greatly enhanced,most significantly,Ba Co_1.8Zn_0.2Fe₁₆O₂₇mixed Bi₂O₃ and BaTi O₃at its thickness of 1.4 mm possesses a bandwidth 10.52 GHz（7.48～18 GHz）with complete coverage in X and Ku bands.