What is RFID Technology and How It Works?

What is RFID Technology and How It Works?

Time:2023-2-16 Author:Frank Chung


Technological advancement has immensely revolutionized the lives of human beings. Before such an advancement, life was hard, difficult and devoid of comfort. Although, over time, human beings have invented, created and developed so many things to make their lives easier, more comfortable and more entertaining, but initially, all of these things were simple and less beneficent. To get the best out of these things, human beings have brought a lot of advancements by using various technologies. Among these technologies, radio frequency technology has proved to be a game changer. Before the advent of this technology, there was a time when we had to physically move to change television channels or to change the temperature of our bedroom AC. Similarly, we had to wait in long queues, sometimes for hours, to get a pass from toll booths. Thankfully, radio frequency technology has not only saved us from all of this fatigue but also has provided us with solutions to many other problems. Currently, this technology is being used in multiple areas, which range from the supply chain, management, and inventory tracking to areas such as counterfeit prevention, pet and livestock tracking, shipping and myriad others. The succeeding paragraphs will further shed light upon radio frequency identification (RFID) technology, its working mechanism and its use cases.   

Background of RFID and a Brief History

The first use of RFID came from World War II when Germans found a way to distinguishably identify the airplanes of friends and foes on the radar. Regarding active RFID tag with rewritable memory, Mario W. Cardullo claims to be the first person who received a U.S. patent on January 23, 1973, whereas Charles Walton was the person who in the same year received a patent for a passive transponder by which a door could be unlocked without using a key.  

Working of RFID

The RFID system employs radio waves to detect and track assets with little or no human involvement and without LOS (Line of Sight). The RFID design consists of three components: RFID tag, transceiver, and antenna. The interrogator (or reader) consists of an RFID antenna and transceiver to emit radio waves to trigger the RFID tag. Like reader, the RFID tags also contain antenna and ICs to receive emitted waves. Once received, RFID tags transmit data signals back to the interrogator, which then converts into a readable format and transfers to a computing database.


RFID tags or chips also contain protective material to grasp all the elements and protect them against environmental conditions. The type of this material is varied depending on the application and use case of RFID systems. In contrast to barcodes, RFID tags are smart and don’t rely on a direct line of sight to track inventory assets, items or animals. RFID system acquires different frequency ranges from the electromagnetic spectrum (EM) to transmit radio waves. The system uses three different types of RF waves:

Low Frequency (LF)

The frequency range of these LF RFID systems lies between 30 kHz to 300 kHz and can read items located at a distance of 10 cm. Compared to other frequency ranges, the LF RFID tags have a limited read range, limited data rate and high production cost, yet these tags operate better in the presence of liquids and metals. Due to their limited read range, these tags are used in access management and livestock tracking.

High Frequency (HF)

The frequency range of these HF RFID systems lies between 3 MHz to 30 MHz and can read items located at a distance of 10 cm to 1 m. These tags are used in electronic ticketing, library books, hotel keycards, contactless payment cards, NFC applications and security systems.

Ultra High Frequency (UHF)

The frequency range of these UHF RFID systems lies between 300 MHz to 30 GHz and can read items located at a distance of 2 m. Compared to other frequency ranges, the UHF RFID tags have a higher read range, data rate and are inexpensive, yet these tags don’t perform well in the presence of liquids and metals as they are more sensitive to EM interference. These tags are used in the supply chain or retail inventory and pharmaceutical industry to prevent counterfeiting and forgery.

The UHF tags are further divided into three sub-categories:

Active Tags

The active RFID tags contain their own power source or battery and transmitter. The function of having an independent power source is to activate the transmitter to transmit the signals periodically and boost the signal strength.

The read range of active RFID tags is typically larger than others, i.e., 300 feet. Due to the presence of a battery, antenna, integrated circuit, onboard tag and sensors, the size of these tags is large. The large size can also increase the cost of these tags, whereas the life span of these tags is limited (3 to 5 years).

Active RFID tags can identify large-sized assets, such as vehicles, cargo, heavy machines, and track industrial or logistics applications.

Passive Tags

Unlike active tags, passive RFID tags don’t contain a battery. They rely on the reader to activate the tag, which sends electromagnetic signals. The tag then reflects the energy back to the reader.

The passive tags are usually small in size, inexpensive than active RFID tags, have a shorter read range (10 feet) and extended operational life (18 to 20 years). Therefore, they offer flexible features to small-scale applications, including supply chain management, access control and item-level tracking.

Semi-passive Tags

Like passive tags, semi-passive RFID tags are small in size, and it is easy to manufacture these tags. These tags contain a power source to improve read distance and data transfer rates, but they don’t have their own transmitters like active RFID tags.

The read range (100 feet) of semi-passive RFID tags is higher than passive RFID tags, whereas the cost is lower than active tags. The operational life (4 to 7 years) of these tags is also limited.  

RFID and Its Comparison with Barcode and NFC


Barcode is an optical-based technology that only reads the item. Moreover, it requires that the item should be in direct contact with the reader and thus, it can only read one item at a time. Furthermore, it lacks an automated system that sorts the items lying in the rack and helps finding the desired item. Besides, it cannot help prevent the theft of items. However, in contrast, RFID is based on a radio frequency that can not only read but also write. In addition, it does not demand direct contact with an item and can read multiple items at a time. Additionally, it can not only sort the items lying in the rack but also saves our time by locating the item through its automated system. Furthermore, it also minimizes the chances of theft of items from the stores.    


Near-Field Communication (NFC) is not alien to the family of RFID technology; instead, it is a member of this technology group. NFC technology can’t operate from long distances and requires the items to be in its proximity. It can read only one tag at a time, owing to which it has limited applications. On the other hand, RFID can operate from a long distance and can read multiple tags at a time. Due to the significant features of RFID, it is now being used in a variety of areas to make our lives easy.   

Advantages and Disadvantages of RFID


  • The deployment of RFID technology renders a convenient, quick, and efficient solution to identify, record, and track objects or items.
  • RFID technology provides security and minimizes the chances of stealing items kept in the store.
  • An RFID reader can scan the tag attached to an item from a long distance.
  • Multiple tags can be scanned simultaneously by using RFID, which not only saves the customer’s time but also maximizes the profit of retailing companies by increasing the tendency of customers.
  • RFID minimizes the traffic jams at toll booths.


  • As RFID requires electricity, it gets inoperative during power outages.
  • Sometimes, RFID reader faces problems while reading the data of tags attached to items made up of metals or containing liquids.
  • In the presence of more than one reader at a time, tags do not respond.
  • Deployment of RFID technology requires knowledge about different types of tags and frequencies, meaning non-technical persons find difficulty during its deployment.

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