Definitions for "Active tag"
An RFID tag that has a transmitter to send back information, rather than reflecting back a signal from the reader, as a passive tag does. Most active tags use a battery to transmit a signal to a reader. However, some tags can gather energy from other sources. Active tags can be read from 300 feet (100 meters) or more, but they're expensive (typically more than US$20 each). They're used for tracking expensive items over long ranges. For instance, the U.S. military uses active tags to track containers of supplies arriving in ports.
An RFID tag that has a transmitter to send back information rather than reflecting back a signal from the reader like passive tags do. Most active tags use batteries as a partial or complete source of power to transmit a signal back tot he reader. Active tags can be read from long distances, but they're much more expensive than passive tags. They're mostly used for tracking expensive items over long ranges.
RFID tags with a battery or other integrated source of energy see Transponder.