RFID stands for Radio Frequency Identification, which is used as a type of Automatic Identification and Data Capture (AIDC) method. Even though most people are not aware of this technology, most of us use RFIDs in our day-to-day life.
RFID operates using the radio frequencies as mentioned above. There are mainly three frequencies used in the RFID field. They are,
Low Frequency (LF) – 125-134kHz
High Frequency (HF) – 13.56MHz
Ultra-High Frequency (UHF) – 860-960MHz
RFID’s consist of two parts, a ‘Tag’ and a ‘Reader’.
Reader is used to reading the ‘Tag’. There are various sized Tags available. Size can vary from Tags that are as big as a mobile phone or smaller than a grain of sand. These Tags could either be ‘Passive’ or ‘Active’.
Passive Tags – This is the cheapest and most commonly used tag type. These Tags cannot act independently as they do not have a power source. The way they get the energy to operate is by the electromagnetic field generated by the reader. Because of that reason these tags have a smaller range compared to Active Tags. These types of tags are used mainly for Access Control, Inventory Management and employee management. The frequency of the tag should match the frequency of the reader in order for them to communicate.
Active Tags – These are more expensive compared to Passive tags. Active Tags contain a power source built inside, which allows them to broadcast their information without a reader’s aid. Because these have a power source, range of these tags is much longer. Also, the tag itself is bigger compared to a Passive tag. Active Tags could be used to locate people or things from a distance (without a close contact opposed to passive tags). These Tags could either be a Beacon or a Transponder. Transponders wait for a signal from a reader, then sends the information out while the Beacons keep broadcasting its information after every pre-configured time. Because of how they operate, Transponders usually have a longer battery life compared to Beacons.
Let’s dive a little deeper to see how the data is being read/written into an RFID tag.
As mentioned above, each tag is equipped with an Antenna and an IC. IC is responsible of sending the data stored in the tag as radio waves and Antenna is used to maximize the range. Once the tag is near a Reader, the Tag’s Antenna picks up an electromagnetic field, it harvests that energy and sends it to the IC and powers it up. Then the IC sends out the data it has through the Antenna. Then the reader captures the signal and interprets it to meaningful data and with little to no human aid, feeds the data into the system. Most of the processes are automated.
There are Read Only, Read-Write, Write-Once Read Many (WORM) Tags. Read Only tags have information written onto them at the manufacturing process. Read-Write tags can be written many times. WORM tags can have more data written but once. The writing process is as same as the reading. Now the reader sends data into the tag via its Antenna so the tag can update/add the received information to its memory.
