Enjoyrfid Technical

Limitations of RFID

Naturally, there are limitations to RFID. Some limitations are due to the laws of physics. Metals and liquids, for example, effectively block radio waves. This is particularly true for UHF and Microwave frequencies. Thus, it is generally not possible to read RFID tags enclosed in metal or surrounded by liquids. There are some advances in tag and antenna design that allow for RFID tags to be placed on metal objects, as long as the tag is not fully enclosed. But in general, RFID does not work very well in environments where the product is surrounded by metals or liquids.

A potential workaround to the problem of fluids and metals blocking RF is to use multiple readers, trying to read a tag from different angles. This will not only improve read rates in the presence of metals and liquids, but also in the general case. A similar method is employed by some companies in an effort to boost read rates of item- or case-level tags on a pallet. In this method, only one stationary reader is used, but the pallet with the cases and items on it is rotated such that the reader “sees” tags in different orientations. This can for example be combined with an existing workstation where the pallet is wrapped with protective tape.

Other limitations of RFID are due to the fact that the application of the technology in logistics operations is still relatively new. RFID tags can be defective (just like barcode labels that may be unreadable because they are torn,dirty, etc.), and to some extent interference issues between readers may exist that prevent tags from being read. It is expected that some of these limitations will find technological solutions as RFID technology becomes more mature in this application.