Active and semi-passive
RFID tags use internal batteries to power their circuits. An
active tag also uses its battery to broadcast radio waves to a
reader. The semi-passive tag relies on the reader to supply
its power for broadcasting. Passive RFID tags rely entirely
on the reader as their power source. The active and semi
passive tags contain more hardware than the passive RFID
tags, hence they are more expensive compared to passive
tags. Therefore Active and semi-passive tags are reserved
for costly items and passive tags are used for relatively
cheaper items.