GHz Electromagnetic Wave Absorption of Hexa and M-type Ferrite

purpose:recently,无线通信工具套件as mobile telephones and computer局域网have become very popular. However，as the number of systems using high frequency electromagnetic waves has increasedserious electromagnetic compatibility (EMC) problems have become apparent. This has led to thesearch for electromagnetic wave absorption materials for the use in the GHz range. in this study电子微波吸收properties of Barium Hexa and M-type ferrite，in which Fe y D13+ y D1 was substituted by (Me d20 .5 y D2Mn y d20 .5 y D2) y D13+ y D1(Me=Sn, Ti, Zr)，were investigated in the GHz频率range.Experimental Procedure：Sintered samples prepared by conventional powder metallurgy and composite samples preparedby crushing these sintered bodies into powders (< 300μm) and mixing with an epoxy resin atdifferent ratios from 40 to 80mass %. The phases present in The samples were characterized by X-raydiffraction (XRD). The magnetic properties were measured using a VSM and a magnetic balance. The electromagnetic waveabsorption properties were measured using a hewlet - packard HP8510C network analyzer in thefrequency range 0.05 to 20.05 GHz.Results：The anisotropy field of Barium M-type ferrite can be changed by varying Thed20 .5 D2Mn d20 .5 D2 content，which enables the natural resonance frequency to be controlledin the range 48ghz to 8ghz . BaFe - d212 - xd2 (Ti - d20.5 - D2Mn - d20.5 - D2) - D2X - D2O - D219 - D2sintered ferrites with compositions x = 2.5 to 5 exhibited good microwave吸收propertieswith minimum rection losses (r.l.) less than - 20db in 1 to 20ghz频率范围，for matching thicknesses (dm) of 0.5 to 3.8 mm. The ferrite-resin composites with 70 mass% ferrite，exhibited wide bandwidths with r.l. < - 20db . In particular，composite samples with compositions x = 3 and x = 4 had wide bandwidths of 14.1 to ~ 20ghz and7.4 to 12.0 GHz, for matching thicknesses of 1.6 mm and 2.7mm，respectively. These matching thicknesses were smaller than for conventional spinel ferrites. It maybe concluded that Barium M-type ferrite is a good candidate for a thin electromagnetic microwaveabsorber in the GHz range. Less

Purpose : Recently, wireless communication tools such as mobile telephones and computer local area networks (LAN), have become very popular. However, as the number of systems using high frequency electromagnetic waves has increased, serious electromagnetic compatibility (EMC) problems have become apparent. This has led to the search for electromagnetic wave absorption materials for the use in the GHz range. In this study, the electromagnetic microwave absorption properties of Barium Hexa and M-type ferrite, in which FeィイD13+ィエD1 was substituted by (MeィイD20.5ィエD2MnィイD20.5ィエD2)ィイD13+ィエD1(Me=Sn, Ti, Zr), were investigated in the GHz frequency range.Experimental Procedure : Sintered samples were prepared by conventional powder metallurgy and composite samples were prepared by crushing these sintered bodies into powders (< 300μm) and mixing with an epoxy resin at different ratios from 40 to 80 mass%. The phases present in the samples were characterized by X-ray diffraction (XRD). The magnet … More ic properties were measured using a VSM and a magnetic balance. The electromagnetic wave absorption properties were measured using a Hewlett-Packard HP8510C network analyzer in the frequency range 0.05 to 20.05 GHz.Results : The anisotropy field (HィイD2AィエD2) of Barium M-type ferrite can be changed by varying the TiィイD20.5ィエD2MnィイD20.5ィエD2 content, which enables the natural resonance frequency (fr) to be controlled, in the range 48 GHz to 8 GHz. BaFeィイD212-xィエD2(TiィイD20.5ィエD2MnィイD20.5ィエD2)ィイD2XィエD2OィイD219ィエD2 sintered ferrites with compositions x = 2.5 to 5 exhibited good microwave absorption properties, with minimum reflection losses (R.L.) less than -20 dB in 1 to 20 GHz frequency range, for matching thicknesses (dm) of 0.5 to 3.8 mm. The ferrite-resin composites with 70 mass% ferrite, exhibited wide bandwidths with R.L. < -20dB. In particular, the composite samples with compositions x = 3 and x = 4 had wide bandwidths of 14.1 to 〜20GHz and 7.4 to 12.0 GHz, for matching thicknesses of 1.6 mm and 2.7mm, respectively. These matching thicknesses were smaller than for conventional spinel ferrites. It may be concluded that Barium M-type ferrite is a good candidate for a thin electromagnetic microwave absorber in the GHz range. Less