What are the classifications of RFID tags?
Among the three types of RFID products, passive RFID has the earliest appearance time of 5261, the most mature 4102, and its application is also the most extensive. In the passive 1653RFID, the electronic tag receives the microwave signal sent by the radio frequency identification reader, and obtains energy through the electromagnetic induction coil, so that the electronic tag completes the information exchange in a short time.
Because the power supply system is omitted, the volume of passive RFID products can reach the centimeter level or even smaller, with simple structure, low cost, low failure rate and long service life. However, as a cost, the effective recognition distance of passive rfid is usually short, and is usually used for close contact recognition. Passive RFID is in the lower frequency band 125KHz, 13.56MKHz, etc.
2. Active RFID.
Although the development of active RFID technology is not long, it has played an indispensable role in various fields, especially in highway electronic toll collection systems. Active rfid actively sends a signal to the radio frequency identification reader through an external power supply. It is relatively large. But it has a long transmission distance and fast transmission speed. Typical active RFID tags can be connected to a radio frequency identification reader 100 meters away, with a reading rate of 1700 reads/sec.
Active RFID mainly works in high frequency bands such as 900mhz, 2.45ghz, 5.8ghz, and has the function of identifying multiple tags at the same time. The long distance and high efficiency of active rfid technology make it indispensable in some applications that require high performance and wide range radio frequency identification.
3. Semi-active RFID.
Passive RFID has no power, but the effective identification distance is too short. Active RFID has a long enough recognition distance, but requires an external power source and is large in size. Semi-active RFID is the product of this contradiction and compromise. Semi-active RFID is also called low-frequency activation trigger technology. Generally, semi-active RFID products are in a dormant state and only supply power to the part of the tag that stores data, so the power consumption is low and long-term maintenance is possible.
When the tag enters the recognition range of the RFID reader, the reader first accurately activates the tag in a small range with a low frequency signal of 125khz, and then sends information to it through 2.4ghz microwave.
In other words, first use low-frequency signals to accurately locate, and then use high-frequency signals to quickly transmit data. Generally, the application scenario is to place multiple low-frequency readers in different locations within a large area covered by high-frequency signals to activate semi-active RFID products. This not only completes the positioning, but also realizes the collection and transmission of information.