All You Need to Know About RF and RFID Tags

The radio frequency identification (RFID) is broadly termed as wireless communication. It incorporates the electromagnetic or electrostatic waves in the radio frequency of the electromagnetic frequency. This enables the identification of a certain object or living organism of interest. Barcodes work on the same principle as radio frequency identification. Both of these technologies are used for the tracking of inventory. However, radio frequency identification is also used for security purposes and is not only used by shops but also healthcare institutions, for shipping, manufacturing, retailing, tracking your pets, fare collection, and even at home.

Wireless Technology

Radiofrequency is a type of wireless communication system that emerged in the second half of the 19th century. This resulted in a new audio system which had the tendency to travel through the air in the form of electricity and magnetic waves through giant transmitters. They travelled through the air by the vibration of air particles.

These waves of electricity and magnetism reached the electronic devices at the receiver end with the tendency to convert the incoming radio waves into electronic signals to produce sounds. This was the beginning of a new era. Once scientists discovered a way to wirelessly transmit data and information, new ideas came into being which are still being widely used today. First audio, then came the prospect of sending images and videos. Since then, many technologies have been invented that have greatly revolutionized the world such as the cellphone and wireless internet.

The Two-Way Transmission

When the innovation of wireless technology emerged, it was quite basic. It involved one transmitter and receiver. Technologies like the radio and the television were the rudimentary inventions in which there was a one-way communication system. Information was sent through the transmitter of the radio or the TV station and was received by the TV or the radio.

Then came the origin of the two way communication with the cellphone and the radar. These technologies harbored both the transmitter and receiver technologies, making wireless communication a bit more complex and sophisticated. The user could now receive and send information as per the requirement. The same way the radar, ships, and airplanes could receive and send signals to the radar tower to obtain crucial information needed to steer these gigantic transportation machines. They worked by sending radio waves and then looking for an echo to make sure their path was clear. Started from this heavy machinery, the radio wave technology was then incorporated into marketing inventory to prevent shoplifting. The items were now tagged with a transmitting radio signal that was caught by the sensors on the exit which set off the burglary alarm, which is still being used.

Credits: MakeaGIF

Working Mechanism of Radio Frequency

The process of this anti-theft mechanism involves the use of three discrete parts; antenna, transceiver, and transponder. The doorway is subjected to an antenna and the transceiver is able to read the RFID tag. The items of the place or a shop have ‘soft tags’ attached to their inner side. In libraries, books have these tags tucked away in one of the pages. Different brands have them placed next to the price tag in the form a sharp metal spike. These tags usually have a certain sort of ink present that bursts in case it is removed by force. They can either be placed subtly in order to catch the shoplifter red-handed or very prominently to avoid the circumstance altogether.

An RFID reader is usually permanently placed at the exit door or can be portable as well. When a person tries to steal an item with an RFID tag and passes through an RFID interrogator, the transceiver sends a radio frequency that activates the antenna in the tag. Once activated, the tag itself produces a small electric current that transmits a specific radiofrequency. The receiver which is hidden on the other side catches the signal and sounds the alarm and the shop lifter is caught.

Deactivating the Radio Frequency Identification (RFID) Tag

The question might arise as to how the RFID tag is deactivated to pass through the RFID interrogator without sounding the alarm. You might have noticed that when you purchase an item, the cashier passes through the item under a specific device. This is the deactivating device. Sometimes its present in the barcode reader itself in order to save the extra hassle.

RFID Frequencies

There are three main types of RFID frequencies; low frequency, high frequency, and ultra-high frequency. It all depends on the country and the region. Some places even have microwave RFID frequency.

  • Low-frequency RFID systems have a range of 30 KHz to 500 KHz, but typically it is found to be 125 KHz. These have short ranges, usually from a few inches to some feet.
  • UHF RFID systems have a range of 300 MHz to 960 MHz and are typically found at a frequency of 433 MHz. It has a range greater than 25 feet.
  • Microwave RFID systems have a frequency of 2.45 GHz and can go for more than 30-plus feet away.

The frequency used in RFID chips depends greatly on where they are being used. When the US State Department announced the use of the smart passports with RFID chips embedded in them, they stated that it could only be read from a distance of four inches. However, things did not go as planned when people complained that their RFID chips can be read from several feet away (33 feet). However, if the need arises, RFID tags can be read from over a range greater than 300 feet.

Radio frequency identification
Credits: Amazon

RF and RFID Tags

There is usually the confusion between the terms ‘RF’ and ‘RFID’. RFID is mostly taken as a broader term which also incorporates RF, however, that is not the case. There is a huge difference between the two terms. In simple words, RF is not as complicated as the RFID. The RF sends one sort of a single that triggers the alarm. You cannot distinguish which of the items set the alarm off while the RFID does, in fact, provide that information and is a bit more complex.

Radio Frequency (RF)

RF tags work on a simple principle. It only transmits one type of frequency hence cannot help identify what item projected it. RF tags use electronic article surveillance (EAS). RF tags set off the alarm when someone tries to steal absolutely anything for the store. However, the surveillance in charge does not have information on what exactly was being stolen because all RF tags project the same sort of frequency.

The most widely used RF tag is a system called acousto-magnetic (AM). This system works quite like the electronic article surveillance, the only difference is that it can scan an item with more speed and from a farther distance as well. Due to these factors, they are most commonly employed by shops for their anti-theft systems.

Radio Frequency Identification (RFID)

As already mentioned, the RFID tags are a bit more complex in their working than RF but this complexity is what makes these tags more preferred. The RFID tags can discretely identify the item from which the radio signal was sent to the receiver. When the radio signal reaches the receiver, it comes encoded with a particular digital code that is specific for each item in the store. RFID machines do not even require batteries to operate. They work solely on the principles of physics hence, are described as passive. The incoming radio waves from a transmitter are enough to activate these RFID chips. The only drawback of these RFID chips is that they can only work at a distance of a few centimeters (10cm). However, there are some active tags that have tiny batteries inside of them, they have the same working principle as the passive tags, however, they can detect frequencies from greater distances.

As an example, suppose you have to get a book from the library and there is a self-checkout. When you scan a book, the RFID tag present in the book will activate when radio waves are beamed on it through the self-checkout machine. The tag will transmit a radio frequency back to this machine along with a code of the book. The rest is done by the computer present there.

Passive RFID tags comprise three components:

  • The antenna – receives the incoming radio waves and projects them back.
  • The chip – generates a specific code for the particular item.
  • The substrate – the object where the antenna or the chip is placed.

RFID or Barcodes?

Both the RFID and barcodes work with the aid of different types of frequency waves. However, there are a few differences. The RFID tags have the tendency to identify the item the tag belongs to without needing a clear line of sight. It also has the ability to identify more than thousands of items simultaneously. If you own an active RFID tag, then it can easily identify objects from several inches or feet away. The read time for RFID tags is less than 100 milliseconds. Whereas, the barcode requires a clear line of sight and can only identify one item at a time at a very close distance. They also take longer to identify an item, typically half a second for every item. Aside from this, barcodes are not read-write. They are attached on the outside of the item and can easily be torn or misplaced. However, RFID tags are much more rugged and last longer.

Credits: Asset Infinity

Various Uses of Radio Frequency Identification Tags

Aside from being used in different stores for the purpose of anti-theft systems, RFID tags now have numerous jobs. They are present on the windshields of different vehicles. These RFID tags help to collect tolls without the cars having to slow down or stop.

Similar is the case with public transport. The radio frequency identification tag of the users detects every individual and deducts the amount of fare from your debit or credit card, as you pass your card through the reader. The RFID tags are embedded in these smartcards for safe portability. There are two categories of smartcards depending on whether they require contact or are contactless.

Another use of these RFID tags is in libraries. They use these tags to keep a check of their books and to offer the people a self-checkout. All they have to do is scan the book they want to take with a self-checkout machine.

The future is looking bright for the technology of these RFID chips. It is deduced that soon these chips might be implanted in people’s passports for a speedy passage through different points at the airport. What makes this technology more interesting is that it is possible that someday it could be planted under your skin. This could save people’s lives, as it would have the ability to send a person’s health report to an emergency report and call for help if he/she meets an accident. Perhaps after the brain chip, Mr. Elon Musk could work on this little theory.


Near-field communication (NFC) enables the transfer of data at a high frequency but a short-range. It combines the interface of a receiver and a smartcard onto a single device. It can allow other devices such as smartphones or any device which has NFC to connect. It works as a combination of a radio frequency identification chip and Bluetooth. NFC is already being used in smartphones as an app called Android Pay and is predicted to be widely used in the near future especially because it is used quite intuitively in smartphones.

Range less than 0.2m Range up to 100m
         <15 milliamperes Power rate varies with frequency
Bi-directional Uni-directional
Bit rate varies with frequency Up to 424 kbit/s
            13.56 MHz LF/HF/UHF/Microwave
No continuous sampling Continuous sampling


Security Concerns

If one owns a smartcard with an embedded RFID with all of their personal information, anyone with a portable interrogator machine can easily read their card. This can give access to one’s personal information to any stranger who owns the machine. The RFID tags are not efficient enough to offer encryption for now, hence, until they do, privacy concerns are a major drawback of these chips. The only exception to these RFID tags are the ones present in smart passports which offer encryptions. These chips have the ability to decode the encryption sent by the reader which offers validity in exchange for the information printed on the passport. The U.S. State Department adopted the BAC system back in 2007 and offered an anti-skimming material to electronic passports to reduce the threat of private information being stolen.

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