RF Shielding: Why It Is A Key Consideration In RFID Projects
RFID’s ability to automate and streamline the tracking and identification of assets has helped revolutionise how numerous industries operate. But as with anything that operates wirelessly, RFID solutions like asset tracking systems are susceptible to unwanted signal propagation and interference. Thankfully, there is a way to solve this, and that is through RF shielding. Read on as we go over why every RFID project can benefit from having some degree of RF shielding.
What is RF shielding?
As its name implies, RF shielding is the use of certain materials that are capable of attenuating or blocking radio frequencies thanks to their conductive properties. Metals are a good example. This shielding effectively creates barriers that keep RF signals from leaving or entering a given area to control the RF environment. This lets the RFID systems operating within to function at optimal performance.
How RF Shielding Can Make RFID Systems Run More Flawlessly
1. Mitigate unintended reads
There are many situations wherein RFID readers must only capture data from a few select tags in a particular area. Retail environments are one such setting where these scenarios come up all the time. For instance, employees at checkout counters will only want to read the items in front of them and nothing else. RF shielding can make each counter a controlled read zone and prevent unintended reads from, say, items located on nearby shelves, and maintain accurate transaction processing.
2. Prevent signal interference
RFID inventory management systems operate at certain frequency ranges, such as in the 860-960 MHz bands commonly used for ultra-high frequency (UHF) RFID. Other wireless communication systems, electronic devices, and even industrial equipment also often emit signals within these ranges, leading to interference that causes failed reads or misreads among RFID tags and readers. RF shielding prevents this severe performance degradation by drowning out external RF noise and keeping the RFID system isolated so that it only detects and processes the intended signals.
3. Improve read reliability and accuracy
Overlapping signals are a common issue in places that use multiple RFID tags and readers. This issue leads to chaotic RF environments and gives rise to the phenomenon called RF collision or crosstalk, severely affecting read accuracy and overall system reliability. However, with the strategic placement of RF shielding materials, these environments can have pockets of isolated zones that enable RFID readers to operate properly without neighbouring readers interfering with their signal.
4. Enhance security
Beyond performance and reliability improvements, RF shielding also helps boost security. One of the top concerns in RFID systems is the unauthorised access to tagged assets or the information in the tags themselves, especially in sensitive applications like those commonly found in government and healthcare facilities. RF shielding allows for creating secure areas that keep signals to make it impossible or at least significantly difficult for unauthorised personnel to interfere with or eavesdrop on the system.
Common Materials Used for RF Shielding
1. Metalised paint and metal sheets
Metal sheets–such as those made from copper and aluminium–offer higher conductivity and thus better shielding performance. They are usually applied to surfaces like enclosures, walls, and so on to create incredibly effective RF barriers.
Alternatively, organisations that need to retrofit their existing structures with RF shielding but prefer not to make extensive modifications can go with metalized paint instead. Unlike solid sheets, this specialised paint can cover a greater variety of surfaces and enhance them with a conductive layer that works just as well at blocking out RF signals.
2. Conductive fabrics
These are a good alternative to paints and feature metal fibres interwoven that work similarly to the metal particles found in the former. As an adaptable solution, conductive fabrics are ideal for those who want greater versatility and for shielding use cases where it’s impractical to use rigid metal sheets.
3. RF absorbing materials
Unlike the previous two mentioned, these materials do not reflect RF signals but completely absorb them instead. Functionally, they serve the same purpose of reducing interference and signal strength. In many applications, RF absorbing materials are typically used in tandem with reflective shielding for the best performance.
Conclusion
RF shielding is a critical consideration in the successful implementation of RFID projects, as it ensures optimal performance, accuracy, and security. Without it, RFID systems are vulnerable to interference, signal leakage, and data breaches, which can compromise efficiency and reliability. As RFID technology continues to expand across industries, addressing the importance of RF shielding early in project planning will be essential for achieving long-term success and stable system performance.
