In modern society, mobile phone has become one of the necessary tools in human life and work. The communicative convenience that mobile phones have brought is noticeable, but they lead to some hidden danger at the same time. It is easy to leak out important messages and cause social problems, especially in government, jail and other vital places. Students often cheat in exams with the help of mobile phones, which damages the justice and equity of the exams. In hospitals, the signal that mobile phone sends will influence the medical instruments badly and leads to medical accidents. In chemistry storage or gas station, the radiation from mobile phone may cause little sparks, and then leads to explosion.    

         Because of the following problems, mobile phone jammer was created. It can solve all the problems easily to ensure the security and secrecy by shielding mobile phone signals. People cannot call others or receive calls from others through mobile phone in the location with mobile phone signal jammer, no matter which mobile phone they use.