How fast can RFID tags be read?

RFID (Radio Frequency Identification) is a technology that uses radio waves to identify and track objects. RFID tags are small devices that can be attached to or embedded in objects, and RFID readers are devices that can communicate with RFID tags and read their data. RFID tags can be classified into two types: passive and active. Passive RFID tags do not have a battery and rely on the reader’s signal to power up and respond. Active RFID tags have a battery and can transmit their own signal.

The speed at which RFID tags can be read depends on several factors, such as:

• The frequency: The frequency is the rate at which the radio waves oscillate. Different frequencies have different characteristics and advantages in terms of read range, data rate, interference, etc. Generally, the higher the frequency, the faster the data rate, but the shorter the read range. RFID tags can operate in different frequency ranges, such as LF (Low Frequency), HF (High Frequency), or UHF (Ultra-High Frequency).

• The protocol: The protocol is the set of rules and commands that govern the communication between the reader and the tags. Different protocols have different capabilities and limitations in terms of tag capacity, collision avoidance, anti-collision algorithms, etc. For example, the EPC Gen2 protocol, which is the most widely used protocol for UHF RFID, can support up to 1,000 tags per second1.

• The reader: The reader is the device that generates the radio signal and receives the tag responses. Different readers have different specifications and performance in terms of power output, antenna gain, frequency range, modulation scheme, data rate, memory size, processing speed, and software features. For example, the ST25RU3993 reader IC from STMicroelectronics can support up to 1,500 tags per second with its high-performance ASIC radio technology2.

• The tag: The tag is the device that stores the data and responds to the reader’s signal. Different tags have different characteristics and performance in terms of chip type, memory size, data rate, encoding scheme, modulation scheme, backscatter power, sensitivity, antenna design, and orientation. For example, the ST25DV-I2C tag from STMicroelectronics can support up to 53 kbps data rate with its fast transfer mode3.

• The environment: The environment is the physical setting where the RFID system operates. Different environments have different effects on the radio signal propagation and reception, such as interference, noise, reflection, absorption, multipath fading, polarization mismatch, etc.

Therefore, there is no definitive answer to how fast RFID tags can be read. It depends on the combination of these factors and their trade-offs. However, some general guidelines are:

• LF RFID tags have a low data rate of about 1 kbps and a short read range of about 10 cm4.

• HF RFID tags have a moderate data rate of about 26 kbps and a medium read range of about 1 m4.

• UHF RFID tags have a high data rate of about 640 kbps and a long read range of about 12 m4.

• Active RFID tags have a very high data rate of up to several Mbps and a very long read range of up to 100 m or more5.

Conclusion

RFID is a technology that uses radio waves to identify and track objects. RFID tags are small devices that can be attached to or embedded in objects, and RFID readers are devices that can communicate with RFID tags and read their data. The speed at which RFID tags can be read depends on several factors such as frequency ,protocol ,reader ,tag ,and environment . There is no definitive answer to this question but some general guidelines can be followed.