active tag
Active tags, as used in RFID and near field communication( NFC), contain small transponders that send the information from the RFID tag to the RFID reader. Unlike passive tags, transponders have a transmitter in addition to the microprocessor and antenna.
Active tags require a battery or accumulator to generate signals. RFID tags and NFC tags are powered by these energy sources and send modulated signals at the appropriate transmission frequency. To ensure the longest possible battery life, the transmission power is relatively low, and energy-saving modulation techniques are used.
In contrast to passive tags, which operate over a limited range of up to 10 m, the distance from which active tags can still be read is more than 100 m. This is due to the fact that the transmitting power of the tags is relatively low. In addition, the transmitting power of RFID readers is much lower than that of passive tags. Active tags are mainly used for tracking high-value goods.