RFID working frequency
At present, the working frequency of RFID products is divided into low frequency, high frequency, ultra high frequency (UHF) and so on. RFID products of different frequencies will have different characteristics.
Low frequency (125KHz~135KHz)
The related operations at this frequency are mainly completed by inductive coupling. There is a transformer coupling between the inductor coil and the reader coil. The voltage induced in the inductor antenna can be rectified by the relative alternating magnetic field of the reader.
- Except for some related effects of metal materials, the general low frequency system can penetrate any material, but it will not reduce its maximum possible reading distance.
- Readers working at low frequencies have no special permission restrictions on the entire planet.
- Low-frequency products have different packaging forms. The disadvantage of the best packaging is that the price is too expensive, but the service life is more than 10 years.
- The sensor works in the low frequency range of 120KHz to 134 kHz. The wavelength of this band is about 2500 meters.
Sensors of this frequency will no longer need coils to wrap. The antenna can be made by etching or printing. The related operation of the sensor is usually completed through load regulation. That is to say, by opening and closing the load resistance on the inductor, the voltage on the reader antenna will change, which can realize the amplitude modulation of the antenna voltage through the remote inductor. If people use data to control the turn-on and turn-off of the load voltage, the data can be quickly transmitted from the sensor to the card reader.
- Except for metal materials, the wavelength of this frequency can pass most materials, but it will shorten the reading distance. The sensor usually needs to keep a certain distance from the metal.
- Although the magnetic field area of this frequency is rapidly reduced, a relatively uniform read and write area can be produced.
- The system has good anti-collision performance and can read multiple electronic tags at the same time.
- Sensors usually exist in the form of electronic tags.
Ultra high frequency (UHF)
Ultra high frequency (UHF) systems will transmit energy through electric fields. The energy of the electric field will not decrease rapidly. The ultra high frequency (UHF) reading distance is relatively long, and the passive system can reach about 10m. It is mainly realized through capacitive coupling.
- This frequency band has a good reading distance, but it is difficult to define the reading area.
- It has a particularly high data transmission rate, and can read a large number of related electronic tags in a short time.
- Radio waves in the ultra high frequency (UHF) band cannot pass through a variety of application materials, especially water, dust and other substances. However, for high-frequency electronic tags, the tag does not need to be separated from the metal.
- Tag antennas usually have two forms: long stripes and tags. The antenna has two different shapes: linear polarization and circular polarization. It is designed to meet the needs of different applications on the market.
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