What is RFID and how does it work?

RFID technology has a history that dates back to World War II. However, it wasn’t until the 1980s that the technology began to be utilized in commercial applications. Today, the RFID system is widely used in various industries and is considered an essential technology. Despite its prevalence, many people still don’t know what RFID stands for. Although explanations can be found on Google, the large number of technical terms and proper nouns used can make it difficult to understand. In this article, TechSparks will provide a simple and understandable explanation of what RFID is and how it works.

Table of Contents

What does RFID stand for?

To make it easier to understand what RFID means, let’s break down the acronym:

  • R stands for “Radio”, which represents radio waves.
  • F stands for “Frequency”, which is the number of times a radio wave oscillates per second. For example, the frequency of a radio station is measured in megahertz.
  • R+F means “Radio Frequency”, which refers to the specific frequency range of radio waves.
  • ID stands for “Identification”, which refers to the process of recognizing and verifying someone’s identity.

Therefore, the full name of RFID is “Radio Frequency Identification”, which represents the technology of identifying an object or person through radio waves of a specific frequency range.

How does RFID work?

Taking a common bus card as an example, it is able to achieve encryption and remote writing without the need for batteries or other energy systems. How is this accomplished?

The credit card machine on the bus acts as both a “transmitter” and a “receiver”. When power is connected, it continuously emits radio waves. When the card is swiped, these waves are transmitted to the card, which activates the signal in the label. The signal is then reflected back to the credit card machine, where the data is decoded and converted. To understand this principle more simply, take a look at the layout of your bus card:

Bus RFID card

The card features a neat row of square coils, along with a small square in the lower right corner, which contains a microprocessor and memory made up of semiconductor modules. When the card is brought close to the card reader, it receives the signal. As the card gets closer, the signal becomes stronger. Once a certain threshold is reached, the semiconductor is energized and converts into electrical energy, activating the circuit. With the microchip in the electronic card, it begins to operate and understands the deduction signal sent by the credit card machine. It then returns a signal indicating a successful deduction. In other words, the RFID system works by combining a scanning antenna, transceiver, and transponder to achieve its operation.

Schematic diagram of how RFID works

RFID applications and cases

We often confuse RFID with barcodes in practical applications. However, they are two distinct concepts. Barcodes require scanning by a scanner, whereas RFID tags communicate with readers via radio waves.

To help you better understand RFID technology, here are a few applications:

  • Transportation;
  • Manufacturing;
  • Retail industry;
  • Intelligent parking lot toll booth;
  • Security system, access control system, intelligent lighting system;
  • Payment cards, student ID cards and even passports;
  • wireless sensor and mesh networks;
  • Intelligent medical equipment, medical device tracking system, patient number identification system.

Why use RFID technology

Advantages of RFID

  • Precise scanning is not necessary as devices can be read by simply placing them in the electromagnetic field. This makes automatic management more efficient.
  • RFID technology can read and store data quickly, allowing for thousands of operations at high speed. This can greatly improve work efficiency and create economic benefits.
  • Label data can be reproduced and modified repeatedly, allowing for the transmission of key data. By converting one-time costs into long-term costs, enterprises can save resources.
  • Radio frequency identification system has fewer limitations compared to traditional methods, such as bus cards that do not require power, contactless operation, and visual inspection. This makes it useful in harsh environments.
  • RFID is considered to be more secure because of its unique and encrypted nature, sometimes even reaching the level of bank cards.
  • Has the advantage of information storage and remote fabrication.

Are RFID radio waves harmful to the human body?

It is commonly believed that electromagnetic waves, including radio waves, can be harmful to the human body. However, current scientific research suggests that the electromagnetic waves emitted by RFID do not have a direct impact on the human body. The radio frequencies used in commercial RFID systems comply with internationally recognized safety ranges, and these electromagnetic waves do not have sufficient energy to cause harm.

Thermal effect: The energy of radio waves can be absorbed by the human body, and exposure to high-intensity electric frequency radiation for a long time can cause thermal effects such as local heating. However, in some typical use cases, the thermal effect of RFID radiation is less than that of the human body’s cooling system, so it is not harmful.

Non-thermal effects: Scientific studies showing any negative “non-thermal effects” of radio frequencies have not been able to be replicated, so harmful effects on humans remain unproven and equivocal. Compared to the electronic devices we use in our daily lives, such as mobile phones, microwave ovens, and televisions, the output power of RFID is much lower, so it is considered harmless.

Implantable: In movies, there are often plots where chips are implanted into the human body for tracking. However, this is an exaggerated and fictional plot and is not a real application of implantable RFID chips. Usually, implantable chips are used for animal tracking management or patient identification in special medical scenarios. The ethics and privacy concerns associated with implantable RFID technology make it controversial and not widely used. Potential hazards include improper implantation position, electrical hazards, or adverse tissue reactions.

Types of RFID?

Property/NounPassive RFIDActive RFIDSemi-Passive/Battery-Assisted Passive (BAP) RFID
Working PrincipleOperates without an internal power source, and utilizes electromagnetic energy from the RFID reader to energize and operate the tag.Powered by an internal battery to operate the circuitry, and can utilize the battery power to transmit radio waves to the reader.Similar to passive tags, BAP tags have a small battery to extend their read range and improve their performance.
LifespanThe lifespan of RFID systems varies depending on the type, and are generally considered to have a longer lifespan as there are no batteries or other components that can fail over time.Tag life is limited by battery lifeIndefinite
Unit CostLower prices and from 0.7 to 2 centsThe highest prices, ranging from $25 to $50 eachModerate, between a few dollars and tens of dollars
Frequency RangeBelongs to low frequency systems around 30 – 300 kHzBelongs to high frequency systems approximately around 30 MHz and 2.45 GHUHF or 2.4GHz
Operating Range(Depends on factors such as RF signal power, antenna performance and sensitivity)It is relatively short, ranging from a few centimeters to several meters, although high-performance passive RFID can achieve read ranges of over 10 meters.According to the application scenario, the active RFID technology allows for high-speed reading requirements to be met, with a range that can extend from tens to hundreds of meters.From a few centimeters to tens of meters
ApplicationsAnimal tracking, access control, car key fob, bus card, etc.Automotive Manufacturing, Mining, Construction, Asset TrackingVehicle identification and logistics management
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