|Active RFID tags have their own
internal power source, which is used to power the
integrated circuits and broadcast the signal to the
reader. Active tags are typically much more reliable (i.e.
fewer errors) than passive tags due to the ability for
active tags to conduct a "session" with a reader.
Active tags, due to their onboard power supply, also
transmit at higher power levels than passive tags,
allowing them to be more effective in "RF challenged"
environments like water (including humans/cattle, which
are mostly water), metal (shipping containers, vehicles),
or at longer distances, generating strong responses from
weak requests (as opposed to passive tags, which work the
other way around).
Many active tags today have practical ranges of hundreds
of meters, and a battery life of up to 10 years. Some
active RFID tags include sensors such as temperature
logging which have been used to monitor the temperature of
perishable goods like fresh produce or certain
Other sensors that have been married with active RFID
include humidity, shock/vibration, light, radiation,
temperature, and atmospherics like ethylene. Active tags
typically have much longer range (approximately 500 m/1500
feet) and larger memories than passive tags, as well as
the ability to store additional information sent by the