Exploring pitfalls in UHF RFID installations

Johannesburg, 18 Jun 2024
Stef du Plessis, Director, Osiris.
Stef du Plessis, Director, Osiris.

Numerous RFID (radio frequency identification) installations fail or don’t perform as expected, owing to myriad reasons. We chatted to Stef du Plessis, a director at Osiris, to explore these challenges and get some advice on how to avoid some common pitfalls and optimise the performance of RFID systems. Osiris Technical Systems has been implementing RFID solutions for over 40 years, across industries as diverse as agriculture, mining, retail, fleet management and hazardous materials storage and transportation.

Du Plessis says there are common mistakes that people make, resulting in their RFID solution not working as intended. He provides a few hints and tips to ensure optimal performance.

  • Mismatched tag-reader compatibility

“It’s important to check whether the RFID reader frequency band matches that of the tags. If not, you may not get the performance you want, resulting in weak reads, data inaccuracies or even skipping some tags altogether.

“If you deploy fixed readers, check that the antenna you use is matched in the same frequency band as both the reader and the tag.”

He says the most common cause of problems is a mismatch of frequencies.

  • Inadequate installation practices

Common mistakes made during the installation phase, such as improper tag placement or inadequate antenna positioning, can lead to signal interference, reduced read ranges and overall system malfunction.

“The angle at which the antenna is mounted can impact the antenna’s output. Something as simple as a person walking between the antenna and the tag could cause interference. You might start getting stray reads if, for example, you have tagged items stored close to your exit but only want to read tags coming through the portal. All these things can impact the system performance negatively.”

He explains: “UHF can bounce or be blocked by a human being, affecting the field, or you could pick up tags outside of the desired field. A defined no-go area for portals that will limit any human movement in that area to avoid false reads will improve performance.

“Also, readers can transmit and read tags through a wall, which may result in tags detected that are not in the intended reading area.”

He suggests that someone who has experience and understanding of the technology be used for installations, in addition to deploying the right technology for the application.

“You need to design the solution to achieve as close as possible to a 100% read for the environment. Length of antenna cables affect the read range and accuracy of reads. Using the wrong (cheaper) cable for an antenna will result in significant losses and a system that delivers sub-optimal results. Choosing the correct antenna for the application is important to have a reliable solution. As an example, if the tags are always in a specific orientation, a linear antenna will deliver better read range. However, if the tags are mostly orientated randomly, a circular antenna will deliver more reliable reads. Lastly, testing the implementation extensively with actual tagged items will illuminate any issues before the commissioning.”

  • Environmental factors

Environmental conditions (eg, temperature, humidity, metallic interference) can have a significant impact on RFID performance and failure to account for these can result in unreliable readings and system downtime.

Deploying RFID in an environment with high humidity will affect reads because the water absorbs the frequency to some extent. For instance, in a region where humidity changes according to season, the range of reading in winter will differ from that in summer. RFID tags don’t work properly directly on metal, so a metal mount tag is recommended. This highlights the importance of using the right tag for the right application.

  • Data management and integration challenges

Du Plessis says while there are several types of readers available, more than one may be required for a successful RFID implementation.

“The advantage of working with a global open standard, such as the EPC Gen2 standard used for UHF, is that any reader/tag that conforms to the standard can be used. This gives the integrator the advantage of not being locked in with a proprietary system. There’s a large variety of handheld, desktop and fixed readers available. Design of the system should start with the right tag. Readers and antennas should conform to the same frequency range. Most of the high-end fixed readers use Linux or Android as the OS.”

  • RFID in the cloud

He advises that businesses deploy a cloud-based platform for data storage and analysis. “This will permit data collected from RF readers to be sent wherever it’s required. With the broad range of connectivity options available, this allows data to be collected anywhere and to be available anywhere. UHF RFID systems produce high-speed reads (up to 1 100 tags per second) and, typically, tags will be read multiple times while they are in the RF field. These reads should be filtered to reduce the volume of data. Typically, a tag will be associated with an item – the process to record this relationship should be very accurate and precise as this will define the value of the data going forward.”

Du Plessis concludes: “Careful planning, know-how and the right technology for the right application and environment, proper execution and ongoing support are all key elements of successful RFID implementations.”