| Although the wide application of electromagnetic wave is convenient for people's life,it has become one of the important environmental pollution sources.Effective absorption of electromagnetic waves can not only improve the electromagnetic environment,but also achieve the stealth effect of military equipment in military field.Therefore,it is an important development direction to research and develop materials with excellent electromagnetic wave absorption performance.The purpose of this topic is the preparation of flexible structure of fabric rather than in the traditional sense of the absorbing material by coating finishing methods such as wave absorption performance,using the method of wet spinning,the different content of carbon nanotube(CNT),silicon carbide(SiC)powder is added to the polyacrylonitrile(PAN)fiber,the yarn has the wave absorption performance is prepared,will it cause multilayer compound fabric woven,and use the vector network analyzer-waveguide system test absorbing performance of the fabric.(1)Several four-layer fabrics all have two obvious absorption peaks in the range of 6-18 GHz,and the higher the content of absorber,the smaller the value of return loss,and the better the absorption performance of the fabric.(2)The CNT/SiC/CNT/SiC four-layer composite fabric was prepared by changing the yarn structure.It was found that the higher the absorbent content was,the better the absorbent effect was,and the peak position of absorbent was basically unchanged,and the absorbent performance was better than that of the single absorbent fabric with the same content.When the facing side is SiC layer,the absorbing effect of the fabric is better than that of the facing side is CNT layer.The minimum reflection loss of the fabric can reach-46 d B at the frequency of 7GHz,and it can attenuate the incident electromagnetic wave by 99.997%.(3)The same content of two kinds of pure CNT and pure SiC four layers laminated fabric to test its wave absorption performance,found the four layers of fabric,relative to a single content of laminated fabric absorbing effect is enhanced,and greatly broaden the absorption of bandwidth,the basic material in the whole frequency band of reflection loss is less than 5db,can decrease more than 90% of the electromagnetic wave,but the premise that the material thickness at the expense of increased absorption of the bandwidth.Use stainless steel fibre blended yarn,stainless steel filament yarn and polyester yarn,and change the layer number of fabric and yarn arrangement than absorbing layer,middle loom weaving stainless steel three,four,five,six layers stitching fabric,using standard test method for the backing plate method and no lining plate method to absorbing performance testing of materials,and compared the differences of the two methods.(1)The absorption peak frequency of the stainless steel multilayer bonded fabric is between6 GHz and 8GHz,and the other frequency bands have no absorption effect.(2)When the mesh size of stainless steel is the same in the stainless steel multilayer bonded fabric,the more the fabric layers,the better the absorptive capacity of electromagnetic waves;When the number of fabric layers is the same,increasing the arrangement ratio between stainless steel staple yarn and polyester yarn will increase the mesh formed by stainless steel staple yarn in the fabric and enhance the wave-absorbing performance of the fabric.When the ratio of stainless steel staple yarn to polyester yarn is 3:1,the minimum return loss value of the sample is-27.6d B,and the corresponding peak frequency is 7.63 GHz.It can attenuate and absorb the electromagnetic wave up to 99.83%.(3)Using the unbacked metal plate test,the inner layer uses the stainless steel filament as the reflection layer,the insertion loss value of the six layers of bonded fabric is about-30 d B,which can shield more than 99.9% electromagnetic waves.(4)Compared with the unbacked metal plate method,the measured absorption rate is lower,but the absorption peak is moving to low frequency. |
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