Influence Of Seam Stitch Type On Shielding Effectiveness For Electromagnetic Shielding Clothing

Under the different frequencies of electromagnetic waves,the human body were affected to varying degrees.Electromagnetic shielding fabric had a certain shielding effect on electromagnetic wave,and can develop protective clothing for electromagnetic protection of human body.Seam Stitch and seam Type were the most basic independent elements in the electromagnetic shielding garment sewing,which were the main cause of electromagnetic leakage.So the seam stitch and seam type design became the key of high electromagnetic shielding clothing design.This article was divided into three parts.It included influence of seam stitch and seam type on shielding effectiveness for electromagnetic shielding clothing,and study on the application of wave absorbing coating in the hole area of electromagnetic shielding clothing.It inquiried shielding effectiveness of on the seam stitch structure parameters by testing system of shielding box method.The design of the structural parameters of the seam stitch were mainly sewing thread type,sewing thread fineness,seam stitch density,seam stitch length,seam stitch number and tracing pattern of single seam stitch in single seam stitch.And curve and line composite seam stitch,composite seam stitch width and complex type composite seam stitch in composite seam stitch;The results shows that ordinary sewing thread is more likely to leak electromagnetic waves than conductive sewing thread;The fineness of the sewing thread should be selected larger than the aperture;The seam stitch density is large,and shielding effectiveness of electromagnetic shielding clothing is also larger;The shielding effectiveness of electromagnetic shielding clothing can be improved by reducing the length and number of seam stitch;The shielding effectiveness fluctuate of broken line and grid curve seam is bigger than that of straight line seam stitch;The composite stitch of curve and straight line can improve the shielding effectiveness of electromagnetic shielding fabric in some frequency range;The composite seam stitch width is wider and its shielding effectiveness is smaller;The more complex seam stitch connection is,the smaller the shielding effectiveness is.Referring to the international standards for seam types and common seam types,and four kinds of seam structures were selected.The wave absorbing sponge,nano aluminum cloth,carbon fiber woven fabric,polyion fabric,and their composite absorbing materials were applied to the seam type respectively.Then adding position of absorbing material were changed into the other position.The change regulation of those shielding effectiveness was emphatically analyzed.The experimental results shows that the shielding effectiveness is different with the different seam types;The shielding effectiveness of seam type b + wave absorbing sponge / nano aluminum material is the largest change and the highest value in the 4-9GHz frequency range than that in the other frequency range;The shielding effectiveness of the absorbing material is changed when the absorbing material is added to the seam types;The shielding effectiveness of seam type b + wave absorbing sponge + carbon fiber woven fabric,which is composite absorbing materials,is significantly higher than that of non absorbing materials and monolayer absorbing materials.Using nickel-coated graphite powder as electromagnetic wave absorber,we explored the absorbing coatings with 15%,37% and 55% absorbents.Then,the effect of different electromagnetic wave absorber on shielding effectiveness of electromagnetic shielding fabric with holes was analyzed.The absorbing coating composited with wave absorbing sponge,graphene fiber and carbon fiber were applied to the hole area of the sleeves of electromagnetic shielding clothing.The effect of multilayer dielectric absorbing layer on shielding effectiveness of electromagnetic shielding clothing was studied.At same time,the multilayer absorbing materials were coated on the electromagnetic shielding clothing sleeve of the front and back of the slot area.The results shows that the content of wave absorber is high,and its shielding effectiveness is relatively high.The coating design of the hole area of the garment sleeve improves shielding effectiveness in some frequency range,and the shielding effectiveness of electromagnetic shielding clothing sleeve of front + coating + graphene fiber increases significantly in the frequency range of 2-3GHz.This paper explore the electromagnetic shielding clothing type of seam and a variety of design method of stitch,summed up the high shielding effectiveness of electromagnetic shielding clothing type sewing and stitch design principles,but has guiding significance to the production,for the electromagnetic shielding clothing broadband within the scope of the design and development to provide the reference.