RFID Systems Are Gradually Replacing Traditional Barcodes. This easy-to-use wireless communication standard enables fast data exchange, making it ideal for applications in transportation, logistics, the food sector, and manufacturing. One of the fundamental components of this technology is the RFID antenna. How does it work, and what should you consider when choosing one?
To better understand how an RFID antenna works, you first need to learn the principles on which the entire technology is based
Radio Frequency Identification.
In the basic version, a reader and a tag are used. The RFID reader consists of a resonant circuit with a coil that functions as both an antenna and a detector, verifying the voltage level in the resonant circuit.
The tag (also known as a transponder or marker) is composed of a resonant circuit operating at the same frequency as the reader and a microprocessor.
The signal sent by the reader’s antenna induces a voltage in the transponder, allowing the transmission of a sequence of information between the devices. Therefore, it can be said that the RFID reader is the brain of the entire system. The antenna, on the other hand, acts as the arm that “reaches” out to the tags, transmitting or receiving information. Both components are essential for the RFID system to function.
The RFID antenna itself does not generate any energy. However, it is able to use the power from the reader to send signals to RFID tags. Without it, this would be impossible.
Unlike the reader, the antenna emits radio waves, not an electromagnetic field. It can emit waves in different directions – this is called circular polarization, or in a single plane – in this case, the polarization is linear, either vertical or horizontal. In the first case, the reader will be able to detect tags around it, but at a shorter range; in the second, the antenna’s range is greater, but it operates in a single plane.
It is important to match the reader antenna’s polarization to the tag’s polarization; otherwise, the range of the technology will be smaller, and it will not function optimally.
Circular polarization works better in situations where many objects need to be scanned in a short period, but the reading accuracy is not particularly important. On the other hand, linear polarization provides precision, but as a result, the process takes a bit longer.
The polarization of the RFID antenna is crucial in selecting the individual components of the technology, but it should not be the only factor determining the choice.
There are long-range and short-range RFID antennas. In a small office covering several dozen square meters, short-range antennas are a better solution. In a spacious warehouse or factory, where approaching working machines is risky, long-range antennas are a more advantageous solution.
In terms of range, pay attention to the operating frequency of the reader. An UHF RFID antenna can communicate with tags over a longer distance than an HF RFID antenna – up to several meters. On the other hand, the range of the lowest frequency LF (classic 125 kHz RFID antenna) is reduced to about 10 cm.
Of course, the size of the antenna affects its range. The larger the antenna, the further the emitted radio waves reach. The maximum dimensions of the antenna are usually limited by the practical use of RFID. A solution that works in a warehouse will not be effective in an accounting office.
The technical parameters of RFID antennas are not everything. Protection against weather conditions also matters.
Just like tags, readers and their attached antennas are divided into those for indoor and outdoor use. In this case, pay attention to the Ingress Protection (IP) rating, which defines the component’s resistance to moisture and dust.
Most components of the system have an IP rating of 50 or 55. This means they are moderately resistant to dust, but not resistant to water, or only to a small extent. If you want to use RFID technology, for example, in an outdoor goods warehouse, consider acquiring a system with antennas that have an IP rating of 65 or higher. Such a component is completely protected against dust, as well as strong jets of water splashing from any direction.
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External antennas can also operate over a wider temperature range. They are suitable for both freezing temperatures and for use in metallurgical plants involved in metal processing.
One of the many advantages of RFID technology is the miniaturization of individual system components. This allows for the offering of various versions of RFID – from retail use to entire gates scanning passing vehicles. The smallest antennas are used in retail. Larger panel antennas are used in logistics, warehouse management, or as a method of access control to rooms.
The correct selection of the RFID antenna is crucial for the functionality of the entire system. Therefore, ensure that the individual components are properly matched so that tag scanning is fast, accurate, and guarantees smooth operation of the technology for a long time.
Are you considering implementing RFID technology in your company? Or are you looking for components of this technology? Contact us so we can help you with this!
