The supermarket security door radio system uses radio waves as the transmitted and received signals, and the detection frequency range is 7. x~8. x MHz. The transmitted signal is a radio signal. It is the same signal as mobile phone and radio, but at different frequencies. The biggest advantage of the radio system is that the system cost is very low and the installation is convenient. However, because its anti-theft label is of loop coil type, the system is vulnerable to interference from some items, such as electronic products such as cash registers, metal objects, etc., causing false alarm or false alarm of the system.