How Do RFID Tags Work?

Wireless communication has taken the way we communicate a notch higher in this day and age. Going by the many benefits of wireless communication, one cannot stop wondering how humanity survived without it in periods past. The use of radio frequency identification is one of the known ways communication has developed over the years.

Surprisingly, many people still do not understand how it works or what RFID tags mean. With an in-depth explanation, there is no doubt that more people will have a better understanding, and there is also a good chance that the communication industry will grow.

What is RFID (Radio Frequency Identification)?

Radiofrequency identification (RFID) is a type of wireless communication that uses electrostatic or electromagnetic coupling in the radio frequency component of the electromagnetic spectrum. This is designed to identify a specific person, animal, or object.

How do RFID Tags Work?

Three main components are used in making up RFID systems: a transceiver, an antenna, and a transponder. The transceiver and scanning antenna combination are called an interrogator or an RFID reader. However, it is noteworthy that there are two types of RFID readers: fixed and mobile.

The RFID reader can be portable or permanently attached as a network-connected device. It uses radio waves to transmit signals, activating the RFID tag. When the activation is done, the tag will send a wave to the antenna, and at this point, it is translated into data.

The transponder may be found in the RFID tag itself. If you look at the read range of RFID tags, you will observe that they vary according to factors, including the RFID frequency, type of reader, kind of tag, and interference in the surrounding environment. The interference can also come from other RFID readers and tags. Tags with strong power sources will also likely have a longer read range.

Why Use RFID Tags and Smart Labels?

To understand how an RFID tag works, you must first know its components, including an antenna, an integrated circuit (IC), and a substrate. There is also the part of the RFID tag responsible for encoding information, known as the RFID inlay.

There are two major types of RFID tags, and they are different based on the power source they use.

Active tags

In an active RFID tag, you will find it has its own power source. This power source is usually a battery.

Passive tags

A passive RFID tag doesn't use a battery but gets its power from the reading antenna. The electromagnetic wave causes a current induction in the RFID tag's antenna. 

Apart from passive RFID tags, there are also semi-passive RFID tags. In these tags, communication gets powered by the RFID reader, and a battery is used for running the circuitry.

The low-power embedded non-volatile memory is an integral part of the design of the RFID system. Usually, RFID tags keep less than 2,000 KB of data and unique identifier/serial numbers. You can have read-write or read-only tags, and in some cases, data can be added through the reader, or existing data may be overwritten.

Many people regard smart labels as simple RFID tags. RFID tags are embedded into an adhesive label in these labels, and a feature barcode is attached. The labels can be used by barcode or RFID readers. With the aid of desktop printers, smart labels can be printed out on demand, especially where RFID tags need more advanced equipment.

The Different Types of RFID Systems

RFID systems are classified into three main types, and these include; low frequency (LF), high frequency (HF), and there is ultra-high frequency (UHF). Apart from these, there is Microwave RFID too. These frequencies differ significantly from one country to the other.

Low-frequency RFID systems

Typically, the frequency is 125 KHz but can be left at 30 KHz to 500 KHz. Low-frequency RFID operates on short transmission ranges from a few inches (centimetres) to anything less than six feet (2 metres).

High-frequency RFID systems

While the typical HF frequency is reportedly 13.56 MHz, it is given a range of 3 MHz to 30 MHz. The standard range can be from a few inches (cm) to several feet (metres).

UHF RFID systems 

The range for these systems can be from 300 to 960 MHz, while the typical frequency of 433 MHz can be taken from a distance of over 25 feet (7 metres) away.

Microwave RFID systems

These systems run at 245 GHz, readings that can be taken from over 30 feet (9 metres) away. The type of RFID application will go a long way in determining the frequency. The actual frequency obtained may vary from the value that is expected.

Typical RFID Applications and Use Cases

RFID can be traced to the 1940s, but it was more commonly used in the 1970s. Due to the high cost of readers and tags, their wide commercial use was hindered. With the decrease in hardware cost, there has been a concomitant increase in the adoption of RFID.

There are several uses for RFID applications, but some common ones include; access control in situations calling for better security, inventory management, vehicle tracking, asset tracking, and equipment tracking.

Can RFID Serve as an Alternative to Barcodes?

There is significant growth in the use of RFID as an alternative to barcodes. The barcode and RFID technologies can be used similarly in tracking inventories, although some significant differences need to be mentioned.

RFID tags can identify individual objects without a direct line of sight. These tags can also scan items positioned inches (centimetres) to some feet (metres) away, but this will also depend on the tag type, and reader used. Although RFID tags require a power source, their data can be updated in real-time.

They have sensors attached to their antenna, which are contained in a plastic cover, making them costlier than barcodes. These tags have a read time of fewer than 100 milliseconds per tag. In the case of barcodes, a direct line of sight is necessary for scanning to take place and closer proximity for scanning than what is seen in RFID tags.

No power source is required, and barcodes are data read-only, which cannot be changed. Barcodes are printed on the outside of objects, making them more subject to fade or wear out. The barcode read time is also half a second or more for each tag.

Some Known RFID Challenges

While RFID technology has some significant advantages, there are two main issues that RFID users will need to contend with.

Reader collision   

This is seen to occur when the signal from one RFID reader interferes with the signal from another reader. The situation can be prevented with an anti-collision protocol which can make RFID tags transmit to their readers in turns.

Tag collision

Tag collisions occur due to too many tags working at the same time. This confuses an RFID reader as a lot of data is transmitted simultaneously. The situation can be prevented by choosing a reader that can collect tag info one after another.

Speak With an RFID Expert 

RFID systems are needed to support the internet of things deployments. It has even been discovered that a lot more may be derived from the technology. For example, suppose the technology is combined with GPS and/or smart sensors technology.

In that case, it may be possible to capture sensor data such as movement, location, and temperature, which may be transmitted wirelessly. All we have now may be no more than scratching the surface of what benefits are imbued in RFID.

If more research is carried out, there is bound to be more sterling discoveries about what use RFID tags may be put to in the nearest future. Talk to an RFID expert if you would like to know more about how they work or have them integrated into your system.