In any RFID system, RFID tags are used for the tracking the objects. A simple RFID tag is a combination of the microchip with the antenna in a package. The package is attached to any system for tracking the object.
The antenna of the tag is used for picking up the signals from the reader or the scanner and then returns signal with additional information attached to it. The size of the RFID tag is very small.
There are three types of RFID tags. They are : Passive, active and semi –passive tags.
Passive Tags: Coming to the passive tags they don’t have any internal power supply. For transmitting the response initially, the complementary metal-oxide-semiconductor (CMOS) is to be powered up. The power is supplied from the minute electrical current which has been induced in the antenna by the radio frequency signals. Then finally the tag sends the information to the tag’s memory.
The advantages of the Passive RFID tags are:
- The passive tags have a life period of about twenty years or more.
- Cost of manufacturing is less.
- They have a wide variety of applications in the consumer goods.
- The size of the tag is very small.
The disadvantages of the passive RFID tags are:
- The tag can read for only short distances. So, there will be lot of limitations because of this property.
- Sensors which use electric power will not be used by the passive tags.
- The readable time of the passive tag is very long.
Active tags: Generally, a battery is being connected to the tag’s circuitary for supplying power to both circuitry and the antenna. Some of the active tags contain replaceable batteries and some of them are sealed units.
The major advantages of the active RFID tags are:
- Compared to the passive one, active tags can be placed at a large distance and can track the product.
- Sensors which use electrical power can be used.
- Monitoring capability
- The capability of initiating communications.
- Highest band width
The disadvantages of the active RFID tags are:
- Without the power from the battery, the active tag cannot be used.
- Compared to passive tag the tag is more expensive.
- The tag is physically larger in size.
- Maintenance cost of the active tag is more than that of the passive tag.
Semi Passive Tags: Semi-passive tags are almost similar to the active tags because they also use a battery for the power supply. Here the power is supplied only to the microchip, but the power will not be supplied for broadcasting the signal. This is used very rarely.
These are the different types of the RFID tags which are used in any RFID system.