Views:2 Author:Site Editor Publish Time: 2019-11-28 Origin:Site
Demystifying the principle of RF anti-theft antenna[BOHANG CHINA]
Many people know about commodity anti-theft devices. In our daily life, we will see them in supermarkets and shopping malls.At present, the two main types of anti-theft devices on the market are AM anti-theft systems and RF anti-theft systems. The two EAS systems are composed of anti-theft antennas, anti-theft tags, and tag decoders/detachers.Some time ago someone said that I don't know what the principle of RF anti-theft antenna is. Today we will introduce it to everyone, and come and see it together.
The center frequency of the RF anti-theft antenna is 8.2MHz, and the sweep frequency is about 1MHz.Two anti-theft antennas at the door are a transmitting antenna and a receiving antenna.A stable electric field is formed between the transmitting antenna and the receiving antenna.The radio system has both soft labels and hard tags,which can protect most items in the mall.
The tag consists of a resonant circuit composed of an inductor and a capacitor, the frequency is about 8.2MHz.The label is attached to the protected product. When the product enters the electric field between the two RF anti-theft antennas, the inductor of the resonance circuit senses the radio wave and resonates at the resonance point, causing the electric field to change instantaneously.The controller amplifies the electrical signal, turns on the speaker power, and triggers an alarm.
Due to the high frequency and high working efficiency, the required transmission power is small, and the RF anti-theft antenna detector can be made slim and delicate.The modulation and demodulation process mostly uses high-tech methods such as digital technology, frequency / phase discrimination, and pulse counting to make the system suitable for use, compatible with hard and soft tags, and reduced false alarm rate.
But because its anti-theft tag is a toroidal coil type, the system is susceptible to interference from some items.Such as cash register and other electronic products, metal objects, etc., cause the system to falsely alarm or not alarm.
The advantages of the RF anti-theft antenna are that the system cost is very low and the installation is convenient.The distance between the two antennas is generally not greater than 1.2 meters, usually used in shopping malls with only one entrance and exit.Now do you have a deeper understanding of the RF anti-theft antenna!