Before an RFID tag can operate reliably on a factory floor, in an engine compartment, or within logistics processes, its behavior must be clearly understood under interference-free conditions. This requires so-called free-field measurements. Experts at Schreiner’s LogiData competence center are among the few providers able to perform this type of analysis entirely in-house.

Such measurements demand generous space and a carefully controlled environment: no vehicles, no reflective metal surfaces, no nearby building edges, and no other sources of interference. Only under these conditions can RFID transponders be measured in a way that reflects their true behavior. “Without free-field testing, we’d only be seeing half the picture,” explains RFID expert Hartmut Wiederrecht. In indoor environments, metal shelving, building walls, or cable installations influence the HF field. Reflections and absorption effects can shift or distort the measurement results.

When the Laboratory Meets Reality

Many tests naturally begin in a measurement chamber, where RFID tags can be compared under standardized, reproducible conditions. However, laboratory measurements represent only part of real-world performance. Free-field tests are the only way to assess how read range, tag orientation, positioning, and the surrounding environment truly affect results. “Good laboratory values,” Wiederrecht notes, “don’t automatically translate into good performance in real applications.” This is why free-field measurements are essential for reliable conclusions. They provide insights not only into the tag itself, but also into the reader used—which in practice often proves to be the dominant system factor. In particular, the sensitivity of the reader’s receiver influences signal return and therefore the achievable read distance. Ultimately, real RFID performance always results from the interaction between the tag, the reader, and the
application environment.

RFID Tags with a Character

As free-field measurements get underway, antennas move in precisely controlled patterns while the measurement software records and plots performance curves. This process, the expert explains, reveals the tag’s “true character.” Understanding this behavior is essential before an RFID-equipped component can be reliably identified in operation. For customers, this translates above all into confidence that their processes will run stably and predictably.

Data for Reliable Performance

Once testing is complete, the equipment is packed away and the collected data moves into analysis. These results form the basis for future customer solutions, helping ensure that RFID delivers consistent performance not only under laboratory conditions, but also in real-world applications.