As a very important communication device, mobile phones have many powerful functions for the transmission of information between users, which may lead to the leakage of important information from some institutions. Many departments have adopted the installation of frequency interference machines to safeguard their own interests. So in places where information must be strictly kept confidential, such as government agencies, banks, examination halls, etc. In some important exams, almost every school installs frequency interference machines to prevent candidates from cheating. During exams such as the final and college entrance exams, as long as the phone enters a blocked area, it will not receive the signal or the signal will be very weak. In addition to these places, frequency interference machines should also be used at gas stations, as gasoline is easily volatile and there are many gasoline molecules mixed in the air of the gas station. Therefore, sparks generated by open flames or other substances can cause explosions. The mobile phones we use have this safety hazard when making calls or sending messages, which may lead to a fire at the gas station.