An RFid system basically has two devices:
1. RFid Tag;
2. RFid Reader.
The RFid tag is a transponder, a small "object" that may be placed on a person, animal, device, or product packaging, among others. Basically it consists of chips and antennas that allows you to respond to radio signals sent by a transmitter base. The RFid tags are divided into active and passive. Active tags send its own identification signal and have a range of tens or hundreds of meters, and generally require a battery that generates energy for this. Passive tags only respond to the signal sent by the transmitting base and usually do not require their own battery or power source, being autonomous. However, its range is lower when compared to active tags. The RFid reader is the equipment containing the information stored in RFid tags and interprets the signal.
Readers can be divided into:
- PRAT (Passive Reader Active Tag - Passive Reader and Active Tag);
- ARPT (Active Passive Tag Reader - Active Reader and Passive Tag);
- ARAT (Active Tag Reader Active - Active Reader and Active Tag).
PRAT readers work with active tags and send no signal itself. These readers wait for the handheld RFid reader to be at the maximum range of the label signal, which is then captured and processed.
ARPT readers send their own signal and work with passive tags. They constantly send a signal when received by a tag, generates in it a response signal which is returned to the reader. The signal sent by the reader has not only communications data but also electromagnetic energy to “feed” the tags in order to receive a reply from them.
ARAT readers send their own signal and work with active tags. By being active, they have a higher range when comparing with tags of a PRAT system, and they do not have the disadvantage of wasteful consumption of the tag battery and the radio signals pollution.