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Radio frequency identification (RFID) is a system used to track the identity of a person or an object by the use of radio waves signals. This identity is in the form of a unique serial number that is attached to that particular item being tracked by a sticker containing a unique number or code. The serial number is contained in a tag called RFID tag, which has in-built antennae to enable it pick signals from the tracker at a given distance away from it and be able to transmit it back. The signal is then analysed by the computer attached to the tracking system, and the information obtained is used according to the required service.
Unlike the use of bar codes, RFID tags have the advantage of being read from a great distance and not necessarily in direct line with the tracker. Radio frequency identification (RFID) technology is mostly used in shopping areas whereby people need not to waste time by having to queue for them to be served. A person just collects all items that he/she requires and simply walks away from the grocery just by positioning the cart next to the tracking system, which will then scan all the items (each with RFID tags) and link the total price to the specific credit card of that person. This can also be used as a security check in various places like the airports or even supermarkets and shopping malls (Miles, Sarma & Williams, 2008).
RFID technology can be categorised into two namely, Fixed RFID and Mobile RFID. The fore is the technology that is used whereby the items being screened are accessed in a particular point. This kind of RFID technology is confined to a certain spot and thus it cannot be changed. On the other hand, if the kind of access to the materials is randomly that is, the antennae from any place regardless of its position can read the items, then that type is known as Mobile RFID. This very much efficient because it allows faster way of accessing the items thus saving time (Glover & Bhatt, 2006).
The RFID system mainly consists of three major components namely the scanning antennae, a transceiver which is used in interpreting data and a transponder (RFID tag) with information about the item.
1. Scanning antennae/Reader
The reader is a device designed in such a way that it has more than one antennae, whereby one emits radio waves signals onto the items to be tracked, while the other antennae does the work of receiving the radio waves signal back from the RFID tag.
2. The RFID tags
These components are found in the form of a sticker and can be attached to an item to enable it get a signal since it has an antennae for transmission. The RFID tags are of two major types: active tag and passive tag. The passive RFID tag do not have its own supply of power, however, it fully depends on the signal from the antennae for it to send back a response signal. These tags can last for a very long period without wastage. Active RFID tags have their own supply of power in the form of small batteries, thus they can be used even when the signal is coming from a very long distance. However, their life span does not last for long due to the expiry of the battery in the tag.
3. Transceiver(Computer system)
This is the system integrated with many decoders. Its major work here is to interpret the data passed from the reader and implementing them into an executable action as per what the system is doing. It could be to show the specification of that item, or it could sound an alarm if it is being used as a security check.
How it works
Generally, the reader antennae are configured to emit radio signals continuously to a specific range within a given area. The frequency of the radio signal that the reader antennae emit depends directly to the power output. This will enable the RFID tags to pick the signal from whatever position it is within that room and read then write data onto it. When the RFID tag is passed through the signal field of the scanning antennae, it will be activated by that signal from the antennae by generating a small electrical current that will make it active.
The RFID tag chip gets the radio waves from the reader then makes them undergo some minor frequency modifications before sending them back to the reader antennae in a different form. The reader will then get the signal sent back and proceeds to rip of the information configured on that particular tag by decoding its contents and passing this information to a computer system(transceiver) for processing as per the required information (Espejo, 2009).
The information decoded from the tag could then manipulated into the necessary data describing the characteristics of that particular item, like the type of that item, its colour or even the price. If RFIDs are used in supermarkets as a form of enhancing the security, then the computer system is configured to sound an alarm if the tag passes without being deactivated. Deactivation of the tags is done by passing the tags through an electronic scanner, which destroys all the electronic components in the tag, hence the tags, will not pick any signal transmission from the antennae, forcing the alarm to sound. Else, if it is not passed through the electronic scanners, the system gives a sound alarm.