Frequently Asked Questions about RFID – 1

Frequently Asked Questions about RFID – 1

Frequently Asked Questions about RFID – 1 2501 1313 Efruz ÖZHÜSREV

What is Automatic Identification?

Automatic identification refers to a broad category of technologies that facilitate the identification of objects. It is often associated with automatic data collection, which involves identifying entities, gathering information about them, and storing the data in a computer system without manual counting. The primary objective of automatic identification systems is to enhance efficiency, minimize data-entry errors, and enable personnel to focus on more valuable tasks instead of manual counting. Numerous technologies fall under the umbrella of automatic identification, including barcodes, smart cards, voice identification, certain biometric technologies (such as retina scans), optical character recognition, and radio frequency identification.

RFID and Barcode systems are Automatic Identification Technologies.

What is RFID?

Radio Frequency Identification (RFID) or “Radio Frequency Identification” is the general name given to the technologies used to identify living things or objects with radio waves. There are many ways of identification, but the most common one is to connect a microchip (known as an RFID tag) to an antenna that identifies a living thing or object, and additional information can be recorded inside the RFID tag to make identification more precise. The reader converts the radio waves received from the RFID tag into data and enables data processable by transferring to a computer system.

Is it better to use RFID than barcodes?

RFID and barcodes are two distinct technologies with some similarities in their applications. The primary difference lies in their operational mechanisms. Barcodes employ a “line-of-sight” approach, necessitating the use of a scanner to read the barcode. Consequently, users must position the scanner in close proximity to the barcode for successful scanning. In contrast, RFID technology does not rely on “line-of-sight” and can read RFID tags within the range of an RFID reader.

Barcodes have certain limitations. If a barcode label is accidentally scratched, damaged, or torn, it becomes unreadable. Moreover, standard barcodes only provide information about the manufacturer and product, failing to identify the object itself or offer detailed product information. For instance, a barcode on a milk carton does not reveal its expiration date.

In contrast, RFID tags can address these limitations. RFID tags are capable of storing unique identifiers and can be read even when embedded within objects or protected by packaging materials. This enables RFID technology to provide comprehensive product tracking and control systems.

Will RFID replace the barcode?

This seems unlikely. Barcodes are efficient and cheap for some tasks, but RFID and barcode tags will co-exist for many years to come.

Is RFID a new technology?

RFID is a well-established technology that has been in use since the 1970s. Historically, it has been costly and had limited applications in enterprise settings. However, if RFID tags can be manufactured at a lower cost, they have the potential to address many of the challenges associated with barcodes. Unlike barcodes, radio waves can penetrate various non-metallic surfaces. This allows RFID tags to be easily read even when placed inside packages or protected from harsh weather conditions. Each RFID tag contains a unique serial number stored in its microchip, making it a globally unique identifier. This characteristic of RFID technology makes it an invaluable tool for product tracking and control systems.

If RFID has been around for so long and is so good, why don’t all companies use it?

Numerous companies are already capitalizing on the benefits of RFID technology. Initially, these investments were primarily focused on closed-loop systems, where products or assets remained within the company’s premises. This was due to the existence of proprietary RFID systems, which meant that an RFID tag affixed by Company A could not be read by Company B if they were using devices and systems from different manufacturers. However, over the past decade, the establishment of international standards has eliminated such incompatibilities.

Another factor driving RFID adoption is cost efficiency. When tracking products within a confined region, companies can reuse RFID tags multiple times. Conversely, in an open supply chain system, where products traverse various stages, it is essential for tags to be inexpensive since they will not be reused after being placed on packages.

In which areas is RFID most commonly used?

The potential applications of RFID technology are boundless, limited only by human imagination. While we previously associated RFID with sectors like logistics and retail, the scope has expanded significantly. Today, we cannot enumerate the sectors and projects that can leverage RFID technology, as it has enabled the realization of numerous projects that were once unimaginable. With RFID, the possibilities are endless!

What are the benefits of RFID?

RFID technology is valuable across various domains, ranging from process tracking to warehouse layout. Its primary objective is to minimize administrative errors, reduce labor lossesduring barcode scanning, mitigate internal theft, prevent shipping errors, and optimize inventory levels. Particularly in the wake of the pandemic, as warehouse and e-commerce operations have witnessed a surge in volume, it has become increasingly crucial for operators to execute error-free and expedited transactions. Currently, the most effective approach to accessing real-time warehouse and inventory records is through the utilization of RFID technologies.

How does an RFID system work?

An RFID system comprises two main components: a tag and a reader. The tag is equipped with a chip and an antenna, while the reader features its own antenna. The reader hardware emits electromagnetic waves, which are received by the tag’s antenna. In the case of a passive RFID tag, it detects the waves emitted by the reader and leverages them to activate the microchip’s circuitry. Subsequently, the microchip modifies the digital information contained within these waves and transmits it back to the reader. For more detailed information on this topic, please click “What is RFID? How RFID Works?”

Why are wave frequencies important?

Just like you use different frequencies on the radio to tune in to different channels, RFID tags and readers must be set to the same frequency for communication. RFID systems employ a wide range of frequencies, with the most common ones being low frequency (around 125 KHz), high frequency (13.56 MHz), and ultra high frequency (UHF) (860 – 960 MHz). In some applications, microwaves at 2.45 GHz are also utilized. Since radio waves behave differently at various frequencies, it is crucial to select the appropriate frequency for each application. Moreover, in recent years, RTLS labels operating at Ultra Wide Band (UWB) frequencies above microwave have become available on the market.

RFID radio waves frequencies

Radio waves frequencies from lowest to highest

How do I know which wave frequency is right for my system?

Different frequencies have distinct characteristics. For instance, low frequency (LF) tags consume less power and excel at detecting non-metallic objects. They are particularly suitable for items with high water content, such as fruits. However, their reading capacity is limited to a maximum range of 30-50 centimeters.

On the other hand, high frequency (HF) tags are better suited for metal objects and can also be used with items containing water. They can be read from a distance of up to 1 meter with ease.

Ultra High Frequency (UHF) tags offer a higher reading capacity and faster data transfer rates compared to low and high frequencies. However, they require direct contact with the object and rely on a clear communication path between the tag and the reader. UHF frequency tags are particularly useful for scanning boxes that enter warehouses through doors.

To ensure you select the appropriate frequency for your application, we recommend consulting with a professional consultant or system integrator.

LF RFID Systems not exceeding 10 centimeters, also called Proximity

Low Frequency (LF) systems are generally produced at 125 KHZ.

High Frequency 13.56 MHZ HF RFID Systems

13.56 MHZ is defined as high frequency.

Ultra High Frequency is defined as UHF

The wave frequency defined as UHF in RFID systems corresponds to 868 MHZ.

Can RFID also be used with sensors?

Yes, it can! Certain companies employ RFID tags in conjunction with sensors that measure temperature, motion, and radiation. By integrating these sensors, some RFID tags can provide real-time information about the temperature of your boxes as they traverse your supply chain. In the food industry, RFID tags that store data such as temperature and humidity have gained widespread adoption. Additionally, sensors are utilized in passive RFID tags to mitigate electrical risks, such as sparks and electrical jumps. Consequently, passive RFID tags equipped with these sensors have become increasingly prevalent in the space and aerospace sectors.

What is the maximum amount of data that an RFID tag can store?

RFID tags can store different amounts of information, depending on the type of tag and the RFID supplier. The most basic information about an object, such as a 96-bit serial number, can fit in a simple tag that can be discarded with the packaging. These tags can only hold up to 2 KB of data, but that is enough for many applications. However, some RFID chip makers have developed more advanced tags that can store much more data and work with the EPC Class 1 Gen2 (including v2) protocol.

What are the differences between read-only and rewritable RFID tags?

There are 3 types of microchips in RFID tags: Read-only, read-write, and write-once read-many (WORM). You can add new information or change the information on the tags that have the write feature while they are in the reader’s range. The serial numbers on these tags cannot be changed. Read-only tags store data throughout production.

What are the differences between passive and active RFID tags?

The transmitter and the power supply of an active RFID tag allow it to send a signal to the reader (similar to how a cell phone communicates with a base station). Passive tags, however, do not have their own power source. They get their energy from the electromagnetic waves sent by the reader, which also stimulate the tag’s antenna. Semi-passive tags use a power source to activate the chip’s circuits, but they need the reader to communicate. Active and semi-passive tags can track high-value assets like train cars over long distances, but they are more costly than passive tags and are not suitable for low-value assets. Some companies are trying to make active tags more affordable. Passive tags are preferred by end users, as they can cost less than 15 dollar cents for 1 million tags or more.

Active, Passive and Semi-Active RFID Tags

What is read range of a typical RFID tag?

In fact, there is no such thing as a typical RFID tag and the reading distance of passive tags depends on many factors: Frequency of operation, reader power, interference with other RF devices, etc. In general, low frequency tags can be read from 0.33 m or less. High frequency tags can be read from 1 m and UHF tags from 3 – 12 meters. When greater distances are required, active tags can support 100 m and more using a power supply.

What is RFID tag collision?

This happens when multiple tags send a signal to the reader at the same time. Different systems are being developed by manufacturers to make sure that the tag responds to the reader only once. These systems include algorithms that remove duplicate tags. Since each tag is read in a fraction of a second, they seem to be read simultaneously.

What is energy harvesting?

Most passive RFID tags reflect waves back from the reader. Energy harvesting is the technique of capturing the energy from the reader for a moment and sending it back to the reader at a different frequency. This technique can significantly improve the performance of passive tags.

What is a chipless RFID tag?

Chipless RFID refers to systems that utilize radio frequencies to transmit data without relying on a serial number stored on a silicon microchip. Instead, some chipless tags employ plastic or conductive polymers as alternatives to silicon microchips. Other chipless tags leverage materials that reflect back radio waves directed at them. By detecting these reflected waves, a computer can utilize them as a unique identifier, similar to a fingerprint, to identify the tagged object.

To prevent unauthorized copying of certain confidential documents, companies are exploring the integration of fibers that reflect radio frequencies into paper. However, chipless tags utilizing these fibers have a disadvantage in supply chain applications: only one tag can be read at a time.

I heard that RFID cannot be used in metal and liquid environments. Does this mean that I can not
use RFID to track cans and liquid objects?

No, it does not. Radio waves reflect off metal surfaces at very high frequencies, while they are absorbed by water. This poses a challenge when tracking products with metal or high water content. However, this issue can be mitigated through effective system design and engineering. In such cases, low and high frequency tags are more suitable for tracking products that contain water and metal. Interestingly, there are applications where low frequency RFID tags are employed to track metal automotive parts. If you are working on projects in metal environments, it is advisable to opt for specialized products designed specifically for such applications.

Find the page that can give you the best products here.

RFID tags may not work efficiently due to reflection from metal environments and absorption in liquid environments.

What is an active reader?

Active readers are readers that can read tags by employing various frequencies or different techniques to establish communication with the reader.

What is a smart and a primitive reader?

While these terms are not universally standardized, the majority of individuals employ the term smart reader to describe a reader capable of data filtering, application execution, and support for various protocols. In essence, a smart reader is akin to a computer that can communicate with tags. Conversely, a primitive reader is a straightforward device that can read only one type of tag using a single frequency and protocol. This type of reader lacks data filtering capabilities and cannot store tag information.

What is reader collision?

A challenge associated with RFID technology is the possibility of reader collision, where the signal from one reader interferes with the signal from another. To address this issue, one approach is to divide the time into multiple passes. This means that readers communicate with tags at different times, preventing collisions. However, this approach can result in a tag being read twice when two readers overlap in a specific area. To avoid this, the system needs to be configured in a way that ensures when a tag is read by one reader, the other reader does not read it again.

For more information on choosing the right reader, you can refer to this page.

What is dense reader mode?

This mode is employed when multiple readers are used in close proximity to each other to prevent interference. Readers switch between different channels within a specific frequency range (e.g., between 902 MHz and 928 MHz in the US) and check for signals before using a channel. If a reader detects that another reader is already using the channel, it switches to another channel to avoid overlapping.

Is RFID harmful to health?

The safety of RFID devices in relation to human health depends on the tags, antennas, and the output power generated by the readers. The energy emitted by passive or active tags when they are loaded is generally considered safe for human health. However, there are specific standards for readers worldwide. In our country, the power of readers must comply with certain levels defined by the Telecommunications Authority. For instance, UHF readers currently available in Europe and our country, manufactured according to ETSI 302-208 standards, produce up to 2W power. This limit falls within the safety guidelines established by European decision makers. To ensure human health, it is recommended that individuals who need to be near the antennas maintain a distance of at least 25-30 cm from these devices. This distance is considered safe for UHF technology.

UHF, HF, Microwave. I don’t understand any of these terms. Which technology and frequency is right for me?

Making this decision requires careful consideration of your project’s specific requirements. Factors such as the type of products you intend to track, movement speeds, reading distances, and numerous other criteria should be taken into account. Our team is well-equipped to provide you with the most appropriate solution and technology tailored to your project’s needs. Feel free to reach out to us today!



With nearly 20 years of management, system analysis, product development and software experience, he leads the digital transformation projects of companies from different sectors. He offers optimized projects and sustainable solutions in the field of information technologies with RFID, RTLS, Pick To Light, IoT and Industry 4.0 solutions, special software and integrations. Follow on LinkedIn

All Posts By: Efruz ÖZHÜSREV
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