Introduction

RFID (Radio Frequency Identification) is a wireless communication technology that uses radio
waves to automatically identify tagged objects or things. It transmits data from an RFID tag to an
RFID reader using an antenna, enabling accurate and real-time tracking.

In this technology, the RFID reader and RFID tag are the two basic components used, where data
is digitally encoded in an RFID tag that can be read by the RFID reader.

The RFID reader is a device that has multiple antennas that transmit radio waves and receive
radio signals back from the RFID tag. The RFID tag uses radio frequency to communicate its
information, including its own identity, to nearby readers.

RFID technology is capable of storing, recovering, and re-recording a vast amount of data (up to
four million characters and thousands of bytes) on a small chip and transmitting it through radio
frequency or radio waves.

RFID technology is widely used in several commercial and industrial applications to search,
identify, track, and communicate with various objects, people, items, or things. It automates the
collection of data and reduces human effort and error. During the reading from the tag, line-of-
sight and item-by-item scanning are not required. Multiple tags can be read by an RFID reader
simultaneously, increasing efficiency.

Components of RFID Technology

Basically, RFID technology consists of four components. They are:

1. RFID Tags
 2. RFID Reader
3. Antenna
4. Software

1. RFID Tags

It is a smart tag consisting of an electronic microchip that has a unique identification number
embedded inside, as well as an antenna. It is also called a transponder.

RFID tags are smart labels that can store a range of information, from serial numbers to several
pages of data, including a short description. For a high level of verification and authentication,
some RFID tags use cryptographic security features.

The tag is located directly on the object to be identified, and an RFID reader can read the data
stored on it from some distance away without direct contact. Unlike barcodes, the line-of-sight of
the reader is not needed in RFID tags. Data can be exchanged between the transponder and
reader device as long as the RFID tag or transponder remains in the electromagnetic field of the
RFID reader/writer.

There are mainly two types of RFID tags:

i. Passive RFID Tag:

Passive RFID tags do not have a power source or batteries. They are powered by the radio signal
transmitted from the RFID reader. They do not require a direct line-of-sight to a reader, but a
shorter read range and smaller size and weight are preferred. These are the most commonly used
tags.

ii. Active RFID Tag:

Active RFID tags have their own power source or battery, and power from the reader is not
required. They can transmit data over a longer distance compared to passive tags. These are less
common tags.

Types of RFID Tags

RFID tags can be divided into three categories based on their power source.

 Passive RFID Tags

 Semi-Passive RFID Tags
 Active RFID Tags

Passive RFID Tags

Passive RFID tags do not have a built-in power source. Instead, they draw power from the radio
waves of an RFID reader. The RFID reader emits these radio waves, energising the passive
RFID tag, which transmits its data to the reader.

The operating range of passive tags varies according to their frequency.

Low-frequency (LF) and high-frequency (HF) tags have a maximum range of about 10 cm and 1
metre, respectively. In contrast, ultra-high-frequency (UHF) passive RFID tags can work up to a
range of 12 metres under optimal conditions.

Passive tags are widely utilised due to their small size (about 1/10th the size of other HF tags)
and cost-effectiveness. They find applications in diverse sectors such as access control, file
tracking, race timing, supply chain management, and smart labels, among others.

Active RFID Tags

Unlike passive tags, an active RFID tag possesses their own power source, typically a battery,
enabling them to broadcast their signal.
Because of their extended range and larger memory capacity, active tags are commonly used in
scenarios where items need to be tracked over a longer distance. Examples include tracking high-
value assets in large warehouses, vehicle tracking in transportation, and real-time location
systems (RTLS) in healthcare settings.

Semi-Passive RFID Tags

Semi-passive or battery-assisted passive (BAP) tags strike a middle ground between active and
passive tags.

Semi-passive RFID tags have their own battery source. However, rather than using this power
source to broadcast a signal as active tags do, the battery in semi-passive tags energises the tag’s
internal circuitry. This additional power supply amplifies the tag’s sensitivity, extending its read
range.

The range of semi-passive tags typically exceeds standard passive tags but falls short of the
range of active tags. They can operate up to a range of approximately 30 metres.

Semi-passive tags are particularly useful in situations where a longer read range than passive tags
is needed but where active tags might be too costly or bulky. This includes tracking shipping
containers in logistics, temperature monitoring in cold chain logistics, and asset tracking in large
facilities.

2. RFID Reader

RFID is the most significant hardware component in RFID technology and acts as the brain of
the system. It transmits and receives radio waves for communication with the RFID tag or
transponder. It is connected to the antenna and receives data from the RFID tag. It also converts
received radio waves into digital data on a computer database.
According to mobility or physical orientation, RFID readers can be classified into two types:
mobile RFID readers and fixed RFID readers. Mobile readers are handheld devices flexible for
reading RFID tags. Fixed readers stay fixed in one location and are typically mounted on walls
or kept on desks or any stationary locations.

3. Antenna

An RFID antenna is a component that regulates the transmission and reception of

electromagnetic waves. It is designed to operate at a specific frequency according to the
application in which it operates.

RFID antennas are often embedded on the RFID reader and are easily accessible for tags.
Depending on the application and operating frequency of the system, the shape and size of
antennas may differ.

4. Software

The software controls the RFID reader and RFID tags in RFID technology. RFID technology
uses specific types of software programs for RFID operations. The software controls the RFID
reader, scanning, and information retrieval from RFID tags. It is used to store data and
information on a local computer or to forward it to cloud storage. RFID software is also
necessary for erasing and reusing RFID tags.
Components of an RFID Tag

Regardless of its type, an RFID tag consists of three primary components: the RFID chip or
integrated circuit (IC), the antenna, and the substrate.

Microchip

The RFID microchip is essentially the ‘brain’ of the tag.

The microchip stores the unique identification information for the object to which the tag is
attached. The average storage range of an RFID microchip is 64 bits to 2 kilobytes. However,
some chips also have additional memory for storing further data about the item.

Furthermore, the chip is responsible for receiving and processing signals from the RFID reader.

Antenna

The antenna is a crucial component of an RFID (Radio Frequency Identification) tag. It’s
designed to receive and transmit signals from an RFID reader.
The size, shape, and type of the RFID antenna can vary widely depending on the application,
frequency of operation, and the level of performance required.

Most commonly, RFID antennas are made of a small coil of wires, with the number of turns in
the coil and the material of the wire affecting the tag’s range and sensitivity.

There are different types of antennas used in RFID tags, such as dipole, loop, slot, and patch
antennas, each with its unique characteristics and advantages.

For example, dipole antennas are often used in high-frequency (HF) RFID systems. In contrast,
patch antennas are typically used in ultra-high-frequency (UHF) systems due to their higher gain
and directivity.

Substrate

The substrate serves as the ‘body’ or foundation of the RFID tag. It is the material onto which
the chip and antenna are mounted.

The substrate is designed to withstand various environmental conditions like heat, moisture,
vibration, chemicals, sunlight, and abrasion that the RFID tag may encounter throughout its
lifecycle. The substrate material is chosen to be resilient and capable of withstanding these
conditions, ensuring that the tag remains functional and intact.

In some cases, a protective layer is added to the substrate to securely attach the RFID tag to an
object. This protective layer can be made of materials like PVC lamination, epoxy resin, or
adhesive paper. The protective layer provides additional protection to the tag, ensuring it remains
securely affixed to the object and preventing damage from external influences.

How Does RFID Works?

The working of RFID technology is based on the principle of inductive coupling, including a
source antenna and a receiver antenna. As we know, each RFID tag has a microchip containing a
unique identification number, model, manufacturing date, expiry date, access information, short
description, etc. The RFID reader accesses such information.
The operation of the RFID process starts with the scanning of an object or item. During
scanning, tags are placed near the RFID reader or vice versa. The RFID reader emits
electromagnetic signals through its antenna, and small coils embedded on the RFID tag pick up
the transmitted signal from the reader. The tag (passive tag) that is nearby the reader is activated
by the power of the reader.

Once the tag is activated, it sends radio waves back to the reader using the same antenna coils
using the inductive coupling (backscatter coupling) method. The reader picks up the
electromagnetic signal of the tag and interprets the frequency and finally translates it into
meaningful data using the software.

The working mechanism of the RFID technology is shown in the above figure.

Types of RFID:

Depending upon the operational frequency, there are mainly three types of RFID systems. They
are:

1. Low Frequency (LF) RFID

2. High Frequency (HF) RFID
3. Ultra High Frequency (UHF) RFID

Low Frequency (LF) RFID:

The range of operational frequency in the LF RFID system is 30 KHZ-300 KHZ. Typical LF
RFID systems work with 125 KHZ or 134 KHZ. There is a shot reading range (about 10 cm) and
slow reading speed in this frequency range. Mostly, the LF RFID system is used in the
application of access control and animal control.

High Frequency (HF) RFID:

The range of operational frequency in an HF RFID system is 3 MHZ – 30 MHZ. A typical HF

RFID system works with 13.56 MHZ with a reading range from 10 cm to 1m. HF RFID systems
are Mostly commonly used in ticketing, payments, and data transfer applications.

Ultra High Frequency (UHF) RFID:

The range of operational frequency in the UHF RFID system is 300 MHZ – 3 GHZ. A typical
UHF RFID system works with 433 MHZ with a reading range of more than 12 m having a very
high data transmission rate. Most RFID projects currently use the UHF RFID systems and hence
making it the fastest-growing market segment.

Applications of RFID:

RFID technology is widely used in several commercial and industrial applications to search,
identify, track, and communicate with various objects, people, items,s or things. Some common
uses of RFID technology are as follows:

 Access control
 Retail sales and supply chain
 Inventory management and control
 Asset Tracking and Equipment tracking
 Vehicle tracking
 People and animal tracking
 Customer service and loss control
 Logistics and Shipping
 Automation on Manufacturing
 Medical and Hospital / Healthcare
 Tollgate system/Electronic road pricing
 Tap-and-go-credit card payment

Advantages of RFID:

RFID Technology provides reliable track and trace services in any environment. It can easily
track and provide accurate and real-time information about inventory and product location.
The followings are the main advantages/benefits of RFID technology.

 Cost-effective solution
 Saving time through automation
 Tracking assets and managing inventory
 Improved data accuracy and availability
 Better control of production
 Shorter process
 Enhanced quality and traceability
 Enhancing health and safety
 Increased revenues
 Rapid payback time

Limitations of RFID:

Besides the numerous advantages of RFID technology, there are some limitations/disadvantages.
Some of them are as follows:

 The cost of implementation is higher as compared to barcode scanners.

 Implementation can be complex and time-consuming.
 Signals from RFID readers can be blocked by any metal surface and thick materials.
 Accuracy is affected by signal quality (any obstruction could cause an error in data).
 Privacy and security problems with increased use of tags (especially personal
information).

RFID vs. barcodes

Using RFID as an alternative for barcodes is increasing in use. RFID and barcode technologies
are used in similar ways to track inventory, but there are some important differences between
them.

RFID tags Barcodes

Can identify individual objects without direct line

Direct line of sight required for scanning.
of sight.

Can scan items from inches to feet away,

Require closer proximity for scanning.
depending on type of tag and reader.

Data can be updated in real time. Data is read-only and can't be changed.
 Require a power source. No power source needed.

Read time is less than 100 milliseconds per tag. Read time is half a second or more per tag.

Contain a sensor attached to an antenna, often

Printed on the outside of an object and more
contained in a plastic cover and more costly than
subject to wear.
barcodes.

How does NFC work?

NFC is based on radio-frequency identification (RFID) technology, which allows compatible
hardware to use radio waves to both controls and communicate with otherwise unpowered and

passive electronic tags!

More specifically, NFC transmits via Electromagnetic Induction, which can induce electric
currents within passive components as well. This means that passive devices can be powered by
the electromagnetic field produced by an active NFC component, and don’t need their own
power supply.

Data is transmitted at a frequency of 13.56 megahertz over NFC. You have the option of sending
data at 106, 212, or 424 kilobits per second. That’s quick enough for a variety of data transfers,
from contact information to sharing photos and music.

NFC Three Modes of Data Exchange

The NFC standard currently has three distinct modes of operation.

 Reader/Writer mode – One-way data transmission where the active device, which may be your
smartphone, establishes a link with another device in order to read data from it. This mode is
used by NFC advertisement tags.

 Peer-to-Peer mode – This enables two NFC-enabled devices to share different types of data.
Both devices transform from active to passive when sending and receiving data in this mode.
Most common use in smartphones.

 Card Emulation mode – The NFC device can be used to make purchases or tap into public
transportation networks as a smart or contactless credit card, i.e. Google Pay and Apple Pay

NFC Solve many Challenges associated with IoT

With a system that aims to collect and transmit data autonomously, there will definitely be some
challenges. NFC is able to help with many of these challenges! Here are some examples:
  NFC makes connecting two separate IoT devices easy and intuitive thanks to its simple tap-and-
go mechanism. Minimal configuration and no wires are required!
 NFC provides data security on many levels. Hackers can take advantage of wide-open networks.
NFC counters with built-in features that restrict eavesdropping opportunities, as well as easy-to-
deploy options for additional security to fit each use case.
 NFC is a strong indication that the consumer wants to take a specific action because NFC chips
must be in near proximity to each other to initiate a transaction. This defends against hackers
gaining unauthorized entry.
 NFC tags will share data passively even if they don’t have power or an IoT link. Users who have
an NFC-enabled computer can tap it to get information like URLs.
 Scalability refers to the technology’s ability to adapt to changes in demand while maintaining its
various functionalities.nfc improves

RFID vs. NFC

Near-field communication (NFC) enables data to be exchanged between devices by using short-
range, high-frequency wireless communication technology. NFC combines the interface of a
smart card and reader into a single device.

Radio frequency ID Near-field communication

Uni-directional Bi-directional

Range up to 100 m Range less than 0.2 m

LF/HF/UHF/Microwave 13.56 MHz

Continuous sampling No continuous sampling

Bit rate varies with frequency Up to 424 Kbps

Power rate varies with frequency <15 milliamperes