What is RFID?

What is RFID

RFID (Radio Frequency Identification) is a form of wireless communication method that helps identify and track objects. It helps to uniquely identify the object in concern.

RFID is everywhere and you may be using it, although you may not be aware of it. For example this technology is in place in public transport systems, libraries, and in some in-store payment systems. Organizations can implement this technology with an RFID solutions provider.

A reader captures the digital information encoded in smart labels called ‘RFID tags’ via radio waves. It is similar to barcoding where the data from a label or tag is captured with a device that contains information in a database.

However, there is a significant difference between RFID technology and the barcode mechanism. The data in an RFID tag can be read outside the line of sight whereas the barcodes should be aligned with the barcode scanner in order to read the data. This notable difference proves that RFID technology is advantageous over using barcode to read data.

RFID technology is very efficient in reading data and is useful when trying to identify or tack objects instantaneously. It reduces the time spent on stock management, which is another one of the major areas in which this technology is in use.

History Of RFID
The history of RFID dates back to World War II (WWII). Another popular form of communication protocol NFC (Near Field Communication), that enables two devices at a distance 4 cm to communicate with each other, is also based on RFID. Its roots can be traced back to this time when Leon Theremin developed a revolutionary musical instrument that could be played without physical touch. It occurred during WWII. This development led to RFIDs to be used to monitor railway carriages during the 1970s. With so many milestones in the development of RFID, credit to its official invention goes to Charles Walton. In 1983, Walton filed the first patent with the term ‘RFID’. From that point onwards, there have been many developments in RFID technology which has led to its widespread use across applications in various industries. Popular retailers including Adidas, Tesco, Decathlon, River Island, and M&S have all incorporated RFID technology within their organizations. Significant increase in sales of up to 5.5% and a decrease in stock holding of up to 13% have been reported with the introduction of this technology.
Technology Used In RFID

An RFID system consists of three primary components; a transceiver, a transponder, and a scanning antenna. The antenna and transceiver, in combination, is referred to as an RFID reader or interrogator.

RFID readers come in two forms; fixed readers and mobile readers. The RFID reader is connected to a portable network and uses radio waves to send signals which activate the tag. The activated tag sends a wave back to the antenna where it is then translated into data.

The transponder is part of the RFID tag. Tags have different read ranges and it is based on factors including RFID frequency, type of tag, type of reader, and interference in the background. Tags with a stronger power source typically have a longer read range.

The tag also functions as a protective material that holds the pieces together to shield it from different environmental conditions. However, this depends on the type of application that it is used for. For example, employee ID badges with RFID tags are made of plastic and the tag is embedded between the plastic layers. 

Here are the details of the two main types of RFID tags:

  • Active RFID: This type of RFID tag has its own power source, which is usually a battery.
  • Passive RFID: This type of RFID tag received power from the scanning antenna. Its electromagnetic wave induces an electricity flow in the RFID’s tag antenna.

Although not commonly used, semi-passive RFIDs also exist, in which a battery runs the circuit and the RFID reader powers the communication component.

What Is An EPC?

RFID technology consists of several guidelines and specifications. However, the main standards of the organization are as follows:

  • International Organization for Standards (ISO)
  • Electronics Product Code Global Incorporated (EPC Global)
  • International Electrotechnical Commission (IEC)

Each radio frequency involved in RFID technology has associated standards. 

An EPC (Electronics Product Code) is a number written to a passive UHF RFID transponder by the manufacturer of a product. The EPC consists of the following components:

  • A GS1 company identifier
  • A product identifier
  • A unique serial number

Quite often, organizations using RFID read EPC numbers to track products along with the category they belong to and manufacturer.

What Is A TID?

A TID (Transponder ID) is a unique number that the microchip manufacturer writes to the transponder’s microchip. This number is a constant and does not change for any reason. The RFID reader does not read the TID. However, it is possible to create a mechanism that authenticates the tag by comparing the TID with the EPC.

Different Frequencies Of RFID

RFID systems fall into three main categories which are determined by their different frequencies. These frequencies also change according to the country and region they are operational in. The three main types of RFID systems are low frequency (LF), high frequency (HF), and ultra-high frequency (UHF). There is also another category apart from these main categories, and it is called Microwave RFID.

Let’s take a look at each of these RFID systems in detail.

  • Low-frequency RFID systems: These RFID systems range from 30 KHz to 500 KHz. However, the most common frequency in use is 125 KHz. LF RFID has short transmission ranges that can fall anywhere between a few inches and six feet.
  • High-frequency RFID systems: These RFID systems range from 3 MHz to 30 MHz. The typical frequency is 13.56MHz, which is commonly seen. The transmission range can be anywhere between a few inches and several feet.
  • UHF RFID systems: These RFID systems range from 300 MHz to 960 MHz with the most common frequency being 433 MHz. They can be read from a distance of more than 25 feet.
  • Microwave RFID systems: These RFID systems run at 2.45 GHz and can be read from a distance of more than 30 feet.

The frequency used generally varies based on the RFID application in focus, with the distances also varying in real-life applications. Whenever longer read ranges are a necessity, tags with additional power can boost transmission ranges to even extend 300 feet.

Maximum Power Used In RFID Technology

Before speaking about the maximum power in RFID systems, let’s look at what is meant by this and the unit used to measure this power.

The reader transmit power or output power in RFID systems is the amount of power transmitted from the RFID scanner to the antenna. The unit of power is decibels-milliwatts (dBm), milliWatts (mW), or Watts. There are three units of power because it depends on the manufacturer’s preference. 

There are dBm to mW to W conversion tables that can help you find the power of RFID systems from various manufacturers.

Now let’s learn what the maximum power used in RFID systems is.

The maximum output power of RFID systems is 30 dBm in most countries. However, some readers have a reader transmit power of 31 or 33 dBm. It is in order to account for cable loss. Therefore, you can determine a range of maximum power in RFID systems between 30 dBm and 33 dBm. Most RFID readers have a minimum transmit power of 0 or 10 dBm.

Some people confuse the difference between the reader’s transmit or output power with system output power. The reader transmit power only takes into account the power sent out by the reader to the interlinked antennas.

System output power is a more advanced and complex calculation that considers several factors including reader transmit power, cable loss, and antenna gain. The results of this calculation is the energy output of the complete system through the antenna.

In most cases, you can customize the power in the RFID reader between the minimum and maximum values. Therefore, the user can make sure that transmit power is actually what he requires for the particular application in use.

There are several factors that impact the read range of RFID systems. However, the increase of an RFID reader’s transmit power will increase the system’s potential read range.

Use Cases

RFID technology is very popular in many parts of the world. It has become a technology that is essential across various industries. You may have even encountered RFID systems in places where you have been to before. However, you may not have been aware that this technology was in existence in the particular application.

An RFID solutions provider is generally responsible for implementing this technology. RFID technology is used across different industries to perform various tasks including the following:

  • Asset tracking and equipment tracking
  • Pet and livestock tracking
  • Inventory management
  • Employee ID badging
  • Personnel tracking
  • Cargo and supply chain logistics
  • Improved visibility and distribution in supply chain management
  • Counterfeit prevention, such as in the pharmaceutical industry
  • Access control in restricted and high-security areas
  • Vehicle tracking
  • Customer service and loss control
  • Manufacturing
  • Shipping
  • Tap-and-go credit card payments
  • Retail sales 

These are some of the most common tasks that RFID encompasses in various industries. There could be various other industries and forms in which RFID systems are in place.

RFID Challenges

With all its advantages and applications across various industries, RFID does come with a few issues. They are as follows:

  • Reader collision: This occurs when a signal from a particular RFID reader interferes with another reader. It can be prevented with the use of an anti-collision protocol to make RFID tags to take chances transmitting to the respective reader.
  • Tag collision: This occurs when a large number of tags transmit data simultaneously, thereby confusing the RFID reader. Opting for a reader that collects tag details one at a time will prevent this issue.
RFID Security And Privacy

One of the main security concerns of RFID is that anyone with a compatible reader can read RFID tag data. Tags can be read after a product leaves a store or supply chain. The main risk is that unauthorized users can read without a user’s knowledge. Also, a tag with a unique serial number can be linked to a consumer which can be identified as a fraudulent activity. The concern is high in healthcare and military applications where it is a matter of life or death or a national security concern.

RFID tags cannot incorporate encryption techniques because they do not have a lot of computing power. The exception to this is RFID tags in passports which use basic access control (BAC). In this case, the chip in the tag has enough computing power to decode an encrypted token from the reader, providing validity of it.

The information on the passport is scanned and used to create a unique key for the passport. The information used here are the passport number, expiration date, and the passport holder’s date of birth, along with a checksum digit for each of these.

In 2007, the U.S. State Department adopted the BAC system to mitigate the threat of any attempts to get hold of passport holders’ personal information, which could go undetected.

RFID And Other Technologies

There are several other technologies such as barcodes and NFC that use a similar concept to RFIDs. However, there are significant differences in these technologies. Let’s take a look at how barcodes and NFC differ from RFID technology.

RFID Barcodes
Can identify objects without line of sightNeed direct line of sight for scanning
Real-time data update possibleRead-only data that cannot be changed
Requires a power sourceDoesn’t require a power source
Read time of less than 100 milliseconds per tagRead time of half a second or more per tag


RFID Near-field communication (NFC)
Works in a single directionWorks in both directions
Range up to 100 mRange less than 0.2 m
Continuous samplingNon-continuous sampling
LF/HF/UHF/Microwave frequency13.56 MHz
Bit rate changes with the frequencyA bit rate of up to 424 Kbps


Final Thoughts
RFID systems are in use in many applications in the US and across the globe. RFID technology is also becoming increasingly used to support internet of things deployment. This technology in combination with GPS and smart sensors, enables sensor data including wireless transmission of temperature and location details.

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