What is Radio Frequency Identification Technology (RFID) and how it works?

What is Radio Frequency Identification Technology (RFID) and how it works?

By carolc

What is RFID and how it works?

RFID (Radio Frequency Identification) refers to a type of technology that enables wireless data storage and identification. The reading and recording of the data is done from devices formed by a chip and an antenna called tags. These antennas are designed to receive radio frequency signals from a reading and recording device called a reader or encoder.

For this communication to exist, the transponder or label does not need to have a battery because a current is induced in its integrated circuit or chip by the electromagnetic field produced by the reader antenna. The current required by the chip is so low that what is induced through the field in its range of action is sufficient to activate it, complete a communication protocol and send information back to the antenna.

The main objective of RFID technology is the identification of any type of product that has attached a tag. This technology has advantages over other existing methods of identification such as barcodes

Types of RFID systems and tags

Within the RFID market there are different types of systems that depend on the frequency band with which they operate. These frequency types are known as:

Low Frequency

Known as LF (low frequency). Covers frequencies from 30Khz to 300 Khz. Provides a reduced reading range of about 10 cm with reduced reading speed. LF is not considered for applications for global use due to the considerable difference in powers and frequencies with which work around the world. It has considerable resistance for external interference.

High Frequency

Known as HF (high frequency). Covers frequencies from 3Mhz to 30Mhz. The vast majority of RFID HF systems work with 13.56 Mhz, presenting reading ranges between 10 cm and 1 m. HF systems are moderately affected by external interference.

Ultra-high Frequency

Known as UHF (ultra-high frequency). Covers frequencies from 300Mhz to 3 Ghz. UHF systems offer coverage of up to 12 m, with a higher level of data transmission and greater sensitivity to interference. UHF systems are much cheaper to manufacture than LF and HF systems.

What types of RFID devices or cards are there?

Passive Rfid Cards

Passive cards are characterized because they depend on an external power source that is only activated by reflecting the waves of the reader or scanner device. They are the cheapest and the distance at which your information can be read is less. They can also be disposable.

Active Rfid Cards

Active cards do not require an external power source but have a built-in battery that powers them. Unlike passive ones, they are more expensive but also have greater read range and data storage capacity. Apart from this, they are better designed to operate at temperature, light, humidity sensors, etc

You are already hearing about the Internet Of the Things, which is nothing more than RFID technology associated with the Internet of Objects, connecting people or appliances to computers via RFID devices. This would mean having people and objects connected to each other online!

Some RFID Applications

Today it is easy to encounter RFID systems both in the everyday, professional and industrial spheres. Some everyday applications are vehicle freezing keys containing chips with low frequency authentication codes, or automatic payment on highways that use active UHF tags.

In the professional field it is applied in the identification of animals through subcutaneous chips that work at low frequency. The identification of people in controlled environments such as access to buildings or areas restricted by RFID HF chips, anti-theft control through EAS (Electronic Article Surveillance) that works in the medium frequency band. Identification and control of luggage in airports by MEANS of UHF tags. In the industrial field where RFID is oriented in the UHF band is the management and visibility of the supply chain, from manufacturing to point of sale as well as its quality control.

One of the applications that arouse interest is that of the digital passport that are being implemented to strengthen the security of airports. It is a new format that includes a chip that allows you to obtain personal information in a simple and fast way. The traveler no longer needs to show his passport, as when passing near an RFID reader, he is fully identified.

Another most commonly used people identification application is with patients in hospitals, as it is one of the key factors for safety. RFID-labeled identification wristbands are used as non-intrusive for people with disorientation or pathologies such as Alzheimer’s or senile dementia to monitor their location at all times.

Another application that is glimpsed is with appliances that allow more efficient and easy use by the user helping to detect expired items in the refrigerator, identify delicate clothing in the washing machine or automatic programming of the temperature of the iron for a type of fabric.

Advantages and disadvantages of RFID technology


  • Non-contact data transfer (also without direct contact)
  • Greater read/write distance and no line of sight needed between tag and reader
  • Higher transfer range
  • Read/write access through different materials (such as wood or paper)
  • Reading multiple RFID chips at the same time (multi-read)
  • Low wear / very resistant depending on the support
  • Possibility of encryption
  • Depending on the type, rewritable
  • The data on an RFID tag can be changed indefinitely
  • RFID technology allows working in harsh environments for operators, i.e. extreme situations of temperature, humidity, etc.
  • The information contained in a tag can be much higher than that of a barcode.


  • Interference by liquids or metals (depending on frequency)
  • Little standardized reader (especially internationally)
  • Transparency and data protection
  • Unlike barcodes, RFID transponders can be read only with the help of a single device
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