Ruddersoft Official Blog - An IT Service Company in India

What Is RFID? How Does RFID Work?

  • Ravi Pal
  • Jul 04, 2023
  • RFID System
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As an AIDC (Automatic Identification and Data Capture) technology, RFID is heavily used in various businesses at present but do you know that RFID is also a prominent IoT technology? Kevin Ashton, the guy behind IoT (he independently coined the term ‘IoT’) was initially working on RFID and later went on to co-found MIT Auto-ID Center with his friends at MIT, USA in 1999. RFID is not a new technology. During World War 2, the British forces used RFID to identify enemy aircraft from the Allied forces (UK, USA, USSR, and France). Then there was the Listening device, an RFID technology-based gift, in the form of the great US Seal that Russia gave to the US ambassador in 1945.

What is RFID?

RFID (Radio Frequency Identification) simply means automatic identification of RFID tagged items using radio frequency signals, remotely. RFID uses a combination of RFID tags, Readers, antennae, and a software system to uniquely identify objects and individuals. RFID tags are available in the form of hard tags, paper labels, inlays and RFID implants that can be attached to objects, animals, or individuals and an RFID reader can be used to enquire the RFID tags.

How does RFID Work?

The working principle of RFID technology is based on radio frequency-based wireless data capture. RFID does not require a clear line of sight, unlike barcoding. However, the working of RFID depends upon the type of RFID tag being used.

In the case of active RFID tags, these tags have their power source in the form of a battery and transmit RF signals on their own that are captured by an RFID reader antenna. The encoded signal is then decoded by the RFID reader and the decoded information is stored in a computer software system for future use in analytics and insights.

When an RFID passive tag or passive RFID tagged item/individual is in the range of an RFID reader, the reader sends an enquiring RF signal which is captured by the RFID-tagged antenna. In Passive RFID tags (RFID tags with no batteries), the RF signal coming from the reader powers the microchip inside the tag which in turn sends the encoded information in the form of an RF signal. The RFID reader captures this RF signal and decodes it for the end user.

In the same way, battery-assisted passive tags/semi-passive tags operate, the only difference being that BAP tags don’t transmit RF signals continuously as active RFID tags do.

The range of RFID systems depends heavily on the type of tag being used. Active tags transmit high energy, strong RF signals which are easily captured by the RFID readers. The range of the Active RFID system is up to 100m while the range of the passive RFID system never exceeds 15m (UHF Passive RFID tags).

RFID Tags and Operating Frequency

Besides the obvious classification of RFID systems/tags on power sources, RFID tags are also categorized based on operating frequency. Besides the obvious classification of RFID system/tag on power source, RFID tags are also categorized based on operating frequency.

There are Low Frequency (LF- 125KHz) RFID tags, High Frequency (HF- 13.56MHz) RFID tags, and Ultra High Frequency (UHF- 860-960MHz) RFID tags.

LF Passive RFID Tags

LF passive RFID tags operate over the low-frequency range, on average 125 KHz. These tags offer the least read range of a few centimeters and are used for POS (point of sale) applications where you have to keep the tag and reader very close.

HF Passive RFID Tags

HF passive RFID tags work on a high-frequency range, on average 13.56 MHz, and offer a read range of 10cm – 100 cm. The HF frequency range is similar to the NFC (Near Field Communication) frequency range as well. These tags are most suitable for proximity cards, smart cards, hotel key cards, and many other applications where the read range requirement is low.

UHF Passive RFID Tags

The UHF passive RFID tags are the most used passive RFID tags/labels. The UHF frequency range varies significantly in different countries as per the frequency spectrum allocated.

•902-928 MHz in USA

•865-868 MHz in Europe

•865-867 MHz in India

•916.7-920.9 MHz in Japan

UHF passive RFID tags offer the highest read range in passive RFID category tags. With a read range of up to 15m, Rain RFID tags find applications in item-level tracking and localization in retail, supply chain and logistics, manufacturing, transportation, utilities, healthcare, education, smart city smart home, etc.

UHF RFID tags are inexpensive, with UHF RFID label prices being under 5 US cents (INR 5-6 going up to INR 30) as of now. These tags offer accurate, high read range and efficiency in inventory control and asset tracking applications, improving asset visibility and order fulfillment, which is crucial for retailers.

RFID Readers and Antennas

RFID Readers

RFID Reader is a device that is used for reading RF signals coming from the RFID tags.

In an RFID system, various kinds of RFID readers are used. Depending upon the use case and the working environment, fixed RFID Readers and handheld RFID readers can be employed.

For outdoor applications or industrial uses, rugged quality RFID readers are used that offer durability and resistance to harsh conditions such as heat, rain, frost, etc. These RFID Readers offer a high read rate - 1200 tags per second to 1800 tags per second and more.

Some of the RFID readers are as follows:

1.Fixed RFID Readers

2.Handheld RFID Readers

3.Integrated RFID Readers

4.Desktop or USB RFID Readers

5.Sled/Bluetooth RFID Readers

6.Android RFID Readers (with display)

7.Wearable RFID Readers

RFID Antennas

RFID antennas are an important component of any RFID system. RFID antennas are used for transmitting and receiving RF signals, for tags as well as RFID readers.

In the case of RFID tags, RFID antennas are built-in, next to the microchip, and in the case of RFID Readers, antennas are built-in (Integrated RFID Readers) as well as employed separately (Fixed RFID Readers).

RFID antennas are available in various shapes and sizes as well as polarization. However, 9dBi (decibels relative to isotropic) circular and linear polarized antennas are widely used in various retail, supply chain, and manufacturing applications.

dBi is a unit that measures the power transmitted by an antenna in a single direction when compared to an isotropic radiator, which transmits signals in all directions. It also refers to as forward gain of an antenna in a single direction.

Various kinds of RFID Antennas that we used are as follows:

1.Far-Field Antennas

2.Near-Field Antennas

3.Ground Antennas

4.Multi Purpose Antennas

5.Circularly Polarized Antennas

6.Linearly Polarized Antennas

7.Proximity Antennas

8.Indoor Antennas

9.Outdoor Antennas

10.Shelving & Cabinet Antennas

How RFID Works as an IoT?

RFID (Radio-Frequency-Identification) is a prominent IoT technology as well. Currently, we have over 15 B IoT devices that are connected to the internet and sensing and sharing data and information.

Like various IoT sensors and devices, RFID tags can be used as sensors as well. When RFID tags work as sensors, they can sense temperature, humidity, fill levels, toxic gases, and more in an indoor or outdoor setting. In Food supply chains and cold chains, RFID tags are used as sensors that effectively collect data on food storage conditions and reduce wastage, that too at low cost.

RFID sensor tags are fabricated using sensing material, material that is susceptible to changes in temperature, humidity, etc. (which depends on the dielectric properties of the materials). These are embedded with the microchip inside the tag and collect sensing data.

Chipless RFID sensors are also becoming popular and provide a great low-cost alternative to IoT sensors. These sensors don’t contain a silicon chip or IC and the fabrication of chipless RFID is quite simple and inexpensive. The information is stored in resonating/reflecting materials that are used in fabrication and encoding is done using time-domain or Frequency domain encoding techniques.

RFID Applications:

RFID technology finds many applications in several industries as followings to carry out various track and trace tasks.

Asset tracking

RFID can be used in various asset-tracking applications. In IT companies, it can be used to track laptops and other IT assets and to fix responsibility in case of asset loss or unauthorized access. RFID tags can also be used to track car keys, wallets, jewelry, etc.

Inventory management

Inventory man is a complex task that requires item-level visibility, identification, and tracking. RFID tags can be used to fulfill all these requirements. The use of RFID tags on pallets, items, and containers ensures accurate inventory management without human errors. It also results in quick auditing and reconciliations.

Access Control System

RFID technology is very helpful in automation and remote access control. The use of RFID cards in hotel rooms, RFID identification cards in office buildings, etc. are a few examples of how RFID technology can be used to allow only authorized persons to enter any building, vehicle, etc.

Livestock Tracking and Management

With the rising cost of manual labor and unavailability of skilled laborers, livestock management is becoming a difficult, non-profitable work. However, the implementation of RFID technology can ensure animal tracking, quick animal count, livestock health monitoring, livestock theft prevention, etc.

Supply Chain Management

In supply chains, RFID is the most important application. Supply chains and retail are what driving the RFID market. RFID tags can be used to tag supply boxes, pallets, containers, vehicles, etc. to ensure inventory visibility and order fulfillment, two of the most crucial supply chain bottlenecks.

The use of active RFID tags can ensure real-time tracking which is crucial for order fulfillment.

Retail Apparel

Another very important use case that RFID finds is retail. In fact, Kevin Ashton, who individually coined the word IoT (Internet of Things) was working on a solution (1999) to solve retail’s most challenging problem: out-of-stock. RFID tags can be used to tag apparel in retail stores and ensure stock counts which are automatically updated. RFID labels can be used on clothes and shoes to identify and help consumers with enhanced customer experience.

POS (Point of Sale) applications of RFID also ensure quick checkouts.

RFID in Healthcare

In healthcare, RFID labels can be used to identify medicines and medical tools. It can also be used for patient Identification and to store health records.

RFID-based access control can be used to ensure that only authorized persons have access to specific areas.

RFID sensors can also be used to monitor the temperature and humidity while storing vaccine vials and medicines.

RFID in Education

RFID technology is also being used for various purposes in the education sector. Apart from RFID-based identification and access control, RFID tags can be used to manage libraries. RFID labels can be used on books, important journals, CDs, and manuscripts to ensure streamlined library operations and prevent theft.

Since the cost of RFID tags and RFID implementation has come down significantly in the last few years, more and more businesses are considering RFID for real-time tracking, inventory management, and supply chain and logistics applications where RFID provides Item-level tagging, visibility, and order fulfillment. The retail sector is the biggest beneficiary of RFID technology as it accounts for the largest RFID market share. RFID tags remain the largest segment of RFID components in the 18.45B USD Global RFID market at present, 2023. It is expected to reach 17B USD by 2024 from 10.23B USD in 2022.

Ruddersoft is a market leader in RFID technology. We provide RFID tags that are fully compliant with ISO 18000-6C, EPCGlobal class1 Gen 2 communication standards. Our UHF RFID tags provide the flexibility to meet customers' needs. Our RFID products are efficient, reliable, and oftentimes can offer better performance across many applications.

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