What is the difference between a Passive and Active RFID system?
Passive technology uses energy emitted by the RF readers to energize passive tags, which emit an RF air signal that is then read by the RF reader and decoded. Since little power is absorbed from the RF signal, the transmission range is less than 10 feet. With no power source to contend with, passive tags have a simplified circuitry, which allows the technology to be miniaturized and therefore can be reproduced at a very low cost, typically several cents apiece. Active technology uses battery power to energize the active tags, allowing the active tags to transmit an effective RF signal up to 300 feet indoors and up to 1,000 feet outdoors. Active RF tags require more complicated circuitry to deal with the powered RF transmission. This complicated circuitry coupled with the powered battery cell make active RF tags larger and more costly than passive RF tags. Active RF tags typically cost $10-$50 each and have an expected life of up to seven years.
