Nowadays, with the rapid development of science and technology, the functions of mobile phones are becoming more and more powerful, and gradually become an irreplaceable important communication tool in people's lives. Of course, there are both advantages and disadvantages. Recently, the negative impact brought by mobile phones is not small. Mobile phones have become a new channel for leak secrets and a means of crime. Therefore, it is necessary to strengthen the control of mobile phones when necessary.

Frequency jammers are mainly used in places that do not need mobile communication, such as various examinations, office space of confidential departments, gas stations, etc. Because of its advantages of convenient installation and simple use, more and more units use frequency jammers. Moreover, the equipment signal is always in a relatively static state, which will not interfere with other electrical equipment, and has also played a certain role in some special places.

When the frequency jammer is working, it transmits a strong signal with the same frequency as the downlink frequency band of the mobile phone, which is tuned to the signal sent from the base station to the mobile phone, so that the downlink signal sent from the base station to the mobile phone is deformed, and the mobile phone cannot recognize it, thus interrupting the connection between the mobile phone and the base station. In short, the main function of the mobile phone shielding device is to make the mobile phone unable to operate normally. Its essence is to implement electromagnetic interference on the wireless network on which mobile phone communication depends, so that mobile phones cannot access the network, and thus cannot receive information from the mobile network, and cannot send information out through the network to achieve the purpose of controlling mobile phones.