cable 有2种屏蔽层:铝箔&编织网,二者有什么区别
确定一下,你说的是Foil Shielding和Braided Shielding是吗?为什么你认为foil屏蔽高频而braid屏蔽低频?有什么理论可以支持吗?
我个人不做网线,所以我并不确定后面的见解是正确的,仅供你参考。
两者都是用来做屏蔽的,没有错。以双绞线为例,foil screen既可以用于overall screen也可以用于element screen,braided screen目前只用于overall screen。举例SF/FTP网线(韩国Daetwyler Class F Patch Cable),外层有braided screen和foil screen,每对线还有自己的foil screen。
就我目前所知,foil screen的屏蔽效能相对较好,但是铝材料不方便作金工/电子屏蔽端接(mechanical/electrical joint with the end of the shield for shield termination.)[1]
Braided screen可以在屏蔽的基础上增强网线的金工强度(mechanical strength),缺点是端接的时候比较耗费人工(the time and effort needed to prepare the cable for attaching a connector.)。[2]
屏蔽线要求测量Transfer Impedance这个参数,可以参考相关的协议标准。[3][4]
附带一些文献,已经很老了,仅供参考。[5]-[7]
Reference
[1] L.O. Hoeft, J.C. Estes, "The role of the drain wire in modern foil cable shields," IEEE Int. Symp. Electromag. Compat., pp.16-19, 9-13 Aug 1993
[2] "Braided Shield Cable Preparation", Radio Magzine, http://radiomagonline.com/tutorials_tips/radio_braided_shield_cable_2/, accessed on 07 April 2011
[3] TIA Standard "Balanced Twisted-Pair Telecomminications Cabling and Components Standards", TIA-568-C.2, Telecommunication Industrial Assossiation, August 2009
[4] ISO Standard "Information Technology - Generic Cabling for Customer Premises", ISO/IEC 11801:2002(E), International Standarlization Orgnization, 2002
[5] E.F. Vance, "Shielding Effectiveness of Braided-Wire Shields," IEEE Trans. Electromag. Compat., Vol.EMC-17, No.2, pp.71-77, May 1975
[6] K.S.H. Lee, C.E. Baum, "Application of Modal Analysis to Braided-Shield Cables," IEEE Trans. Electromag. Compat., Vol.EMC-17, No.3, pp.159-169, Aug. 1975
[7] L.O. Hoeft, J.L. Knighten, "Measured surface transfer impedance of cable shields that use combinations of braid and foil and are used for 1 Gb/s data transfer," IEEE Int. Symp. Electromag. Compat., Vol.1, No., pp.527-531, 24-28 Aug 1998
好像在哪看到过一些说法,印象中,要求对电磁波屏蔽的电缆是有两层屏蔽网的,一层单点接地屏蔽电场,一层屏蔽磁场。
觉得铝箔应该是屏蔽电场的,编织网是屏蔽磁场的(因为里面含有铁?),但是屏蔽具体怎么接法不清楚
继续关注这个问题!请各位大大们多多指教
恩,看错了……
昨天看的cable的说明,明确说了foil for frequency above 50MHz ,other way, braide for bellow 50MHz.
电缆仿真有人做过吗?数值算法的?
学习了,非常好
测试频率是多大? 如果想100%的不辐射,那你的买硬同轴cable了
申明:网友回复良莠不齐,仅供参考。如需专业解答,请学习本站推出的微波射频专业培训课程。
上一篇:微带线滤波器设计
下一篇:直接弯个线圈然后并联一电容为什么测不出谐振点?