What are the different types of RFID tags?
March 9, 2012 § Leave a comment
In this blog post I will investigate RFID tags.
There are three types of RFID tags:active, passive, and battery assisted passive tags. All three types have a central chip and an antenna.
Active tags have their own on board power source. This makes them quite a bit more expensive and bigger than passive tags. The power source helps the tags to be read from much greater distances, from 20 metres to 100 metres.
Active tags can work at much higher frequencies usually 455 MHz, 2.45 GHz, or 5.8 GHz. The tag can always broadcast a signal because of the on-board power source or they can become active when they come in contact with a scanner. Active tags can have a memory as large as 128 kilobytes. Active tags can have other uses, such as data logging and temperature sensing.
Passive tags are much smaller and cheaper than active tags. Passive tags also contain a lot less memory than active tags. Usually a product identification number is stored in the memory. The information stored in the tag is unique so two books that are the same can be told apart by this unique data.
Because they work at much lower frequencies than active tags, they can only be read from very short distances usually from a couple of centimetres to about ten metres. The RFID tag becomes active when it comes in contact with a reader. The reader can always broadcast its signal or come on when needed. The energy from the reader is stored in a capacitor in the tag.
Battery Assisted Passive RFID tags are different to passive tags as they have a small battery. This makes them a lot better in some cases because it does not need to get energy from the RFID reader to wake up. This also increases the read rate and reliability of the tag. Some battery assisted passive tags can be read from 45 metres away.
Weinstein Ron. (2005, May/June). RFID: A Technical Overview and Its Application to the
Enterprise. IT Pro, 27-33.