The cell phone cannot make or receive calls due to cell phone jammer

The cell phone in the shielding range will lose signal from the base station for cell phone jammer. Foreign successfully prepared carbon nanotube / epoxy composites [15] [14] greatly increased wear and tear, so you can play a very thin thickness of the shielding effect. Tests showed that the 100 ~ 1000MH z frequency range, [19] aluminum foam shielding effectiveness up to 65 ~ 90dB, and the smaller interior holes, the better the shielding effect. Another category is foamed plastic foam material, in recent years, porous foam as a new type of foam, has attracted increasing international attention. Porous foam plastic bubble diameter is generally 01 to 10 microns, cell density at 109 ~ 1015 /.The cell phone cannot make or receive calls due to cell phone jammer. Or so, before the material density foam than 5% to 98% strength to weight ratio can be increased by 5 ~ 7 times show prospects. [20], has a very broad issue 4 new shielding technology and shielding absorbing electromagnetic shielding structure, the traditional technical measures, mainly based on apertures, operation, display devices, as well as several other aspects of the cable shield, using the Shield technology is mostly a single layer shielding and shielding materials, mostly. Traditional single electromagnetic shielding materials and there are many shortcomings, and present a new multi-screen as the shielding means, capable of wide-band high-energy within the effective electromagnetic pulse protection.
Scientific exploration and knowledge innovation and technology on the principle of electromagnetic shielding of
1 Introduction With the development of electronic technology, it is used in the production of life more and more electrical and electronic equipment, automobiles, electronics, communications, computers and electrical equipment into a large number of families, electromagnetic waves radiate electromagnetic energy at an annual 7 % -14% annually, electromagnetic environmental pollution is getting worse. The slow-start circuit design of cell phone jammer can effectively avoid the sparking phenomenon when switching on cell phone jammer. On the other hand, electrical and electronic equipment to increase the sensitivity of the external electromagnetic environment, electrical and electronic equipment due to the increasingly digital, highly integrated, small to quantify the signal level to meet their high-speed, light weight and small size requirements, highly vulnerable to external electromagnetic interference to malfunction, leading to serious consequences.
This phenomenon is called skin effect., because of the presence of eddy current reflection of electromagnetic waves into space, part of the electromagnetic energy penetration inside the conductor to form a thin layer of the conductor surface electromagnetic waves, and finally put through conduction current part of the energy dissipation of Joule heat.