RFID electronic tag category

RFID electronic tags are divided into three categories: passive, semi passive (also known as semi-active), and active.

Passive RFID electronic tag

Passive tags do not have an internal power supply. Its internal integrated circuit is driven by received electromagnetic waves, which are emitted by RFID readers. When the tag receives a signal of sufficient strength, it can send data to the reader/writer. These data not only include the ID number (globally unique identifier ID), but also data pre stored in the EEPROM of the RFID electronic tag.

Due to the advantages of low cost, compact size, and no need for power supply, passive tags are preferred. The RFID tags on the market are mainly passive.

Semi active RFID electronic tag

Generally speaking, the antenna of a passive tag has two tasks: first, to receive electromagnetic waves emitted by the RFID reader to drive the tag IC; second, when the tag returns a signal, it needs to switch between 0 and 1 based on the impedance of the antenna. The problem is that in order to achieve the best return efficiency, the antenna impedance must be designed between "open circuit and short circuit", which will cause the signal to be completely reflected and unable to be received by the tag IC. Semi active tags are designed to solve this problem. A semi-active RFID electronic tag is similar to a passive RFID tag, but it has an additional small battery that can power the tag IC, keeping it in working condition. The advantage of this is that the antenna can be used for transmitting signals without the task of receiving electromagnetic waves. Compared to passive RFID tags, semi-active RFID tags have faster response times and better efficiency.

Active RFID electronic tag

Unlike passive and semi-active RFID tags, active RFID tags themselves have an internal power supply to supply the power required by the internal IC to generate external signals. Generally speaking, active RFID electronic tags have a longer reading distance and larger memory capacity, which can be used to store additional information transmitted by the reader/writer.