What is RFID? Learn Its History, How It Works, Types, and Its Applications

Radio Frequency Identification (RFID) is a technology known to be useful for identifying objects using electromagnetic waves. The tags are the main component of this technology, which works by using radio waves.

Radio frequency identification technology enables the identification and tracking of goods, assets, or people. The advantages offered by this technology are efficiency and ease of access without direct contact.

Are you familiar with RFID technology? Read this article to the end to learn about its definition, history, how it works, and regulations governing its use.

What is RFID?

Radio Frequency Identification (RFID) is a wireless technology device that uses radio signals to identify specific targets or objects, as well as read and enter data. This device consists of two parts to operate, namely RFID tags and RFID readers. 

RFID tag

A device attached to an object to be identified by the reader. Tags can be passive or active. 

• Active tag: Has its own battery and can read and write data over long distances. 
• Passive tag: Does not have a battery and obtains power from the radio signal emitted by the reader. 

RFID reader

A device used to scan codes on tag devices. Like tags, readers also come in passive and active types.

• Active reader: Emits signals to activate tags and receives responses. 
• Passive reader: Only receives signals from active tags. 

History

The history of RFID can be divided into three parts: its origins and initial concepts, development and patents, and standardization and adoption.

The technology emerged during World War II from the development of radar to identify allied fighter planes. In 1948, Harry Stockman published a theory about the possibility of sending data wirelessly, which became the basis for Radio frequency identification. The development of passive began in the 1960s, leading to the emergence of various technological variations. 

The first development of RFID resulted in an electronic toll system in 1973 by Mario Cardullo, who patented the first passive radio transponder with memory. In 1983, modern technology was patented by Charles Walton for its application in door lock systems. 

The use of this technology expanded into various fields in the 1970s and 1980s. Its development included industrial asset tracking, nuclear fuel, and security systems.

In the 1990s, ISO and ANSI played an important role in focusing on Radio frequency identification standardization to ensure interoperability. By 1999, efforts to standardize the system began at MIT.

RFID technology was increasingly adopted in the 2000s by large companies such as Walmart. Today, this technology has become an integral part of many aspects of daily life, from toll cards and attendance systems to contactless payment systems such as debit and credit cards. 

How it Works?

RFID devices can function if there are two components, namely tags and scanners. Tags containing chips are attached to objects that will be identified or read. Then the information stored in the tag will be transmitted via radio waves to the scanner. Here’s how it works in detail:

• The scanner sends an electromagnetic signal to the tag.
• This signal activates the chip in the tag. 
• The activated tag chip sends the unique information stored in it to the scanner.
• The information in the tag is read or modified by the scanner.
• The information from the tag received by the scanner is sent to the system being used, such as WMS.
• The system becomes the processing and storage center for all information received from the tag.

This identification process can be done remotely, depending on the signal quality of the scanner and the type of tag used.

Parts of an RFID Tag

To help you understand the RFID systems and the differences between tags, inlays, and labels, you need to know the parts of an RFID tag. The following are the parts that make up an RFID tag:

• Integrated circuit: This part is also known as an RFID chip. It is the part of the tag that is responsible for storing, managing, and processing data.
• Antenna: This part receives radio waves from the interrogator and sends data back to the reader. This part takes up the most space.
• Substrate: The substrate is the material that holds the IC and antenna of the tag together.
• Surface: The surface is a thin layer made of clear/white plastic or paper. It is used to cover the antenna and chip.
• Casing: This refers to the cover that surrounds the IC, antenna, and substrate. It is made of PET, plastic, or paper.

Understanding Each RFID System

1. RFID Inlay

The first RFID system is the inlay, which is a basic component consisting of an integrated circuit, antenna, and substrate. The antenna is made of aluminum, silver, and copper, and is attached to polyethylene terephthalate (PET). This component functions to identify and track objects wirelessly using radio waves.

There are two types of RFID inlays: wet and dry. Wet RFID inlays have a surface that contains adhesive between the antenna and the cover paper.  This type is relatively easy to apply directly to surfaces such as packaging or products and can be removed and reattached.

Meanwhile, dry inlays do not have adhesive, so the antenna and chip placed on the PET substrate are not yet in the form of a label. This type requires the use of external adhesive or other materials to help attach it to assets.

Inlays are relatively affordable and easy to use.  This RFID systems is also very flexible because it can be integrated into various products, such as cards, key chains, or ready-made hard labels. In addition, its application can be implemented in various industries, such as logistics, retail, and access control.

2. RFID Label

An RFID label is a system component that has the same contents as an RFID inlay, namely an antenna, chip, and substrate. This component functions to automatically identify and track objects without the need for direct contact.

An RFID label is an RFID inlay embedded in paper. This system is also known as a smart label. It is applied in several sectors, such as logistics, healthcare, and sporting events. 

This system is used to track shipments and manage the movement of goods in the supply chain in the logistics sector. In the healthcare sector, it is used to track medical equipment and manage drug inventories. Meanwhile, in sporting events, it is used to track the time and route of runners in a race. 

3. RFID tags

RFID tags are components of the system that have encapsulated chips and antennas. Their purpose is to protect the tag components and ensure ease of implementation.

RFID tags can be active or passive. Active tags are equipped with batteries, which ensure a relatively wider reading range. Passive tags, on the other hand, rely on signals from the reader to be activated. This system is used for automatic tracking of various objects in the retail, logistics, healthcare, and other industries. 

The Difference Between RFID Inlays, Labels, and Tags

Although inlays, labels, and tags share the same basic purpose in building RFID systems, they differ in construction, readiness for use, surface, and purpose.

Construction

• RFID Inlay: Has an unwrapped chip and antenna construction.    
• RFID Label: Has the same construction as an inlay embedded under an outer layer (paper/polyester) with adhesive.
• RFID Tags: The construction is in the form of a standalone device, which can be in the form of a label, card, or other hard form.

Usability    

• RFID Inlay: Not ready for use as it needs to be converted into a finished product.
• RFID Label: Ready for use and can be applied immediately as it has adhesive.
• RFID Tags: Ready for use as they are already in device form.

Surface    

• RFID Inlay: Has a clear and transparent surface, with no special printed surface.    
• RFID Label: Has a printed surface for text, barcodes, etc.    
• RFID Tags: Have a printed surface or not, depending on the form.

Purpose    

• RFID Inlay: Intended to be the basis for making labels or other RFID products.
• RFID Label: Designed for easy-to-apply product labeling and tracking.
• RFID Tags: Designed for general asset tracking, either in the form of labels or hardware devices.

Types of RFID

adio frequency identification (RFID) has various types, each designed to meet specific needs in various applications. Based on various sources, here are some commonly used types:

Based on the power source

Passive

Passive RFID tags do not have batteries and rely on energy from the RFID reader signal. Therefore, this type only has a short reading range. It is often used for animal identification and basic access control. 

Active

Active RFID tags are equipped with their own batteries and are capable of transmitting stronger signals. This type has a wide reading range of up to hundreds of meters. It is often used for long-distance asset tracking. 

Semi-passive

Semi-passive RFID tags have an internal battery but still rely on signals from the reader to communicate. This type has a better reading range than passive tags and is more efficient than active tags. They are often used for monitoring the temperature of goods, tracking environmental conditions, and monitoring the storage temperature of medicines.

Based on memory

Read-only

Read-only RFID tags have static characteristics. They can only read information.  The stored data is also permanent and cannot be changed after the tag is produced. 

Read and write

Read and write RFID tags have dynamic characteristics. They can read and rewrite information. Data stored in the tag can be updated or added to the initial data that has been written. 

Based on radio frequency

Low Frequency (LF)

This type operates at low frequencies (LF), usually between 125-134 kHz. The reading range of LF types tends to be short. Examples of applications include access control and pet identification.

High Frequency (HF)

This type operates at high frequencies (HF), typically at 13.56 MHz. The reading range for HF types is around 1 meter. Examples of applications include smart cards, electronic payments (NFC), and access control.

Ultra-High Frequency (UHF)

This type operates at ultra-high frequencies (UHF), typically between 860-960 MHz. The reading range for UHF types is up to several meters. Examples of its application include logistics, supply chains, and inventory management.

The selection of RFID type depends on specific application requirements, including read range, environmental resistance, and implementation costs. This diversity allows the technology to be widely applied across various industries and scenarios.

RFID Functions in Everyday Life

The main function of RFID is to identify and track objects wirelessly, thereby improving efficiency, accuracy, and security. Here are some of its functions:

• Payment systems: Facilitate cashless transactions, such as on transportation cards.
• Access control: Secures access to certain areas or systems, so that only authorized persons can enter. 
• Attendance management: Automatically records the attendance of employees or visitors when they tap their RFID cards.
• Inventory tracking: Automatically identifies and counts the number of products without manual intervention in large warehouses or distribution centers.
• Asset management: Automatically tracks the usage history, location of goods, and assets.

RFID Radio Frequency Type

RFID radio frequency types are divided into three categories: low, high, and very high. The following is an explanation of each type of frequency.

Low Frequency (LF) RFID 

Low-frequency (LF) RFID is a system that operates within the 30 kHz to 300 kHz frequency range. Low frequencies have a reading range of up to 10 cm.

This type of frequency is resistant to interference from metals and liquids. However, it has a slower speed compared to other types of frequencies. 

Common standards for LF RFID include ISO 14223 and ISO/IEC 18000-2. LF tags are used in access control, livestock tracking, and other applications where a short reading range is acceptable.

High Frequency (HF) RFID

High-frequency (HF) RFID is a system that operates in the 3 MHz to 30 MHz frequency range. High frequencies provide a reading range of 10 cm to 1 m.

This type of frequency has better and faster data transfer speeds than low frequencies. Additionally, it operates effectively in humid environments and on objects that contain water. However, it is quite sensitive to radio wave interference.

Common applications include e-ticket payments and data transfer. Near Field Communication (NFC) technology is based on HF RFID and has been used for payment cards and hotel key cards. Other types of smart card and proximity card payment and security systems also use HF technology.

Applicable standards for HF RFIS include ISO 15693, ECMA-340, ISO/IEC 18092 (for NFC), ISO/IEC 14443A, and ISO/IEC 14443 (for MIFARE and other smart card solutions). 

Ultra High Frequency (UHF) RFID

Ultra-high frequency (UHF) RFID is a system that operates in the frequency range between 300 MHz and 3 GHz. This frequency offers a reading range of over 12 meters. 

This type of frequency has the fastest data transfer speed. However, it is more sensitive to interference from metals, liquids, and electromagnetic signals. Some of these issues are being addressed in the development of new design innovations.

UHF tags are often used in retail inventory tracking, drug counterfeiting prevention, and other applications that require a large number of tags. The common standard for UHF RFID is the global EPC Gen 2/ISO 18000-6C, which is widely recognized for its use in tracking applications.

LF vs HF vs UHF RFID Tags Differences

RFID radio frequency types differ from one another. The differences include frequency, read range, data transfer speed, interference resistance, and general use. In short, LF RFID has the shortest read range but performs well in metal and liquid environments.

Additionally, HF RFID has a medium read range and is used for applications such as contactless payments. Meanwhile, UHF RFID has the longest read range and fastest speed, making it ideal for large-scale logistics and inventory tracking.

Here are the differences in more detail:

RFID Power Supply Types

RFID based on power source refers to the power source used by the tag to operate. Based on this power source, RFID is categorized into three classifications: active, passive, and semi-passive.

The following outlines the three types of RFID power sources, their advantages, disadvantages, and their applications in everyday life.

Active RFID Tags

Active RFID tags are powered by internal batteries, allowing them to transmit radio signals independently. Each type of active tag has a different number and shape of batteries. The batteries are used to transmit signals continuously or at specific intervals.

• Advantages: Long read range of up to hundreds of meters, real-time tracking, and high accuracy.
• Disadvantages: Large size, high cost, limited lifespan due to battery life, and difficulty in producing thin cards.
• Applications: Industry, logistics, real-time traffic management, electronic wireless communication, vehicle access control, etc. 

Passive RFID Tag

Passive RFID tags do not have batteries. Their operating power is obtained from the RFID reader. When in proximity to the RFID reader, the antenna converts the received electromagnetic wave energy into electrical energy. This activates the chip inside the RFID tag and transmits the data stored within it.

• Advantages: Small size, lightweight, low cost, service life of more than 10 years, maintenance-free, various shapes, and many available applications.
• Disadvantages: Due to the lack of an internal power source, the reading distance is limited. Generally, a high-power RFID reader is required.
• Applications: Security tracking, retail inventory management, access control (key cards), library document tracking, file management, animal tracking, etc. 

Semi-passive tag

Semi-passive RFID tags combine the advantages of active and passive tags. Semi-passive tags use an internal battery to power their circuits, but still rely on signals from the reader to reflect data. 

Under normal conditions, these tags do not operate in an inactive state and do not transmit RFID signals to the outside environment. They only start operating when they enter the range of a low-frequency activator signal, and the label is activated.

• Advantages: Compared to passive tags, semi-passive tags have faster response speeds and better efficiency. Compared to active tags, semi-passive tags consume less power. They have a wider range, lower cost, and are equipped with features such as environmental sensors, making them suitable for applications like cold chain tracking. 
• Disadvantages: Limited range and battery life.
• Applications: Access control management, accurate personnel and object positioning, area monitoring, parking management, automatic toll systems, and monitoring of sensitive environmental conditions, among others.

How to Choose RFID Tag Power Supply

Choosing an RFID power supply type depends on several key factors, including read range, cost, and the specific application. Here’s how to choose the right one:

• Determine the read range requirements: For short-range applications, passive tags are more suitable. For long-range applications, active or semi-active tags are more necessary.
• Consider the cost: You can adjust the cost when using these tags. Passive tags are the cheapest, followed by semi-active tags, and active tags are the most expensive.
• Know the usage requirements: For heavy-duty tasks such as monitoring high-value assets, it is best to use active tags. Passive tags are suitable for simple identification.
• Understand the environmental conditions: For use in harsh environments with metal or liquid interference, active tags are better. Passive tags are generally used in controlled, non-metallic environments.

The Type of Memory on Gen 2 RFID Tags

1. EPC Memory

EPC (Electronic Product Code) memory is designed to store unique codes used to identify individual products in supply chains and applications. This memory can also be programmed with custom codes, such as service numbers, inventory numbers, or serial numbers.

This memory bank of Gen 2 RFID Tags has a minimum storage capacity of 96 bits, which is sufficient for many applications. Some RFID tags also allow additional space from user memory to be allocated to EPC memory.

The main function of EPC memory is to efficiently track and manage products. Examples of its use are typically in supply chains, asset management, and industry.

2. TID Memory

TID (Tag Identifier) memory is designed to store the unique identification number of an RFID tag. This identifier is read-only and is set by the manufacturer when the chip is created.

The memory bank of this Gen 2 RFID tag has a length of between 32 and 80 bits and cannot be changed or deleted after production. The beginning of the TID indicates the manufacturer, with each company having a unique set of codes.  

The main function of TID memory is to assign a globally unique identification number to each tag. Examples of the use of this memory are typically for inventory asset management, animal tracking, and automatic authorization.

3. User Memory

User memory is designed to store additional data outside of the EPC, such as temperature or maintenance log data, expiration dates, additional serial numbers, or to group tags for specific functions. This memory can be configured with access restrictions for security, such as locking certain blocks so that only authorized users can read or write the data.

Some RFID chips of this type are equipped with user memory of varying sizes, depending on the tag, ranging from a few hundred to thousands of bits, for example, 512 bits, 4k, or 8k. A well-known example is the Monza 4QT chip, which provides 512 bits of user memory. However, other RFID tags offer much larger storage capacities, reaching up to 4 or even 8 kbit.

The main function of user memory is to store additional data. Examples of its use include inventory management, product identification, asset tracking, and attendance systems.

4. Reserved Memory

Reserved memory is designed for security-related data, specifically blocking passwords and access passwords. This memory cannot be used to store user data, but only for applications that require sensitive data security. 

This type of RFID is equipped with a special memory bank (bank 00) that stores two 32-bit passwords: an access password and a delete password. The access password is used to lock and unlock the write function on the tag, while the delete password is used to permanently deactivate the tag, although this feature is rarely used. 

The main function of user memory is to store passwords that control access to other memory banks. An example of its use in retail is to allow the cashier system to deactivate RFID tags, thereby preventing security alarms from sounding when customers leave the store. 

How to Choose Memory Type Gen2

When choosing Gen 2 RFID Tags, you need to consider several factors, ranging from identification purposes to additional data requirements and industry standard compliance. You also need to look at the cost of each memory type in order to choose the best one.

For standard asset or inventory identification, EPC memory is sufficient, whereas for additional security and remote deactivation, you will need to choose reserved memory. Additionally, for additional data requirements, user memory can be an option as it offers a sufficiently large capacity. 

As a standard, most industrial applications use EPC memory. For global supply chain applications, compliance with the GS1 EPC standard is required. In terms of cost, EPC memory is also more affordable compared to the more expensive user memory.