RFID Reader Problems and How to Avoid Them
1. The sensitivity of the RFID reader
The range limitations of RFID tags are a thing of the past. Today’s state-of-the-art tags require very little energy and can be powered over a range of more than 20 meters. To achieve these ranges, RFID readers need to be able to pick up even weak signals from farther tags. In many successful RFID projects, the sensitivity of the wireless RF reader is mission critical. To overcome this challenge and improve reader accuracy and read rates, a new generation of readers needs to be highly sensitive and able to handle variations in tag parameters, such as tolerance to backscatter link frequency (BLF), and changes in system parameters, such as phase shift.
2. The lack of standardization of RFID readers
RFID readers must comply with ISO and GS1 standards, as well as radio regulations, etc. Testing readers of existing standards is not only difficult, but also a lengthy and time-consuming process. In fact, only part of the test is done reasonably efficiently. Engineering teams struggle with time pressure, lack of automation, or simply knowledge about the standards required for prescriptive testing. This can easily lead to insufficient test coverage for the reader and writer. In order to make all wireless RF readers on the market more comparable based on the values defined by the Gen2 protocol, while improving the performance of RFID deployments, the measurement of link timing, physical layer and RF envelope parameters is essential.
3. The gap between RFID readers
The term “Reader Gap” first appeared in 2017, when a new generation of RFID tag chips had a read range of more than 20 meters. While this sparked a lot of enthusiasm from system designers, a shortcoming soon emerged that the overall range achieved was often much lower than that. The “reader gap” determines the operating range loss of the RFID system due to the lower performance of the RFID reader receiver. Operating range is the actual range or distance that can be achieved in the application. The minimum distance of the forward link from the RF reader to the tag is determined by the maximum transmit power, usually limited by radio regulations, and the tag’s minimum operating power, Pmin. The return link from the RFID reader to the tag is determined by the backscattered power Pback of the tag and the receiving sensitivity of the reader. In order to build a bridge between the tag and the reader, the receiving sensitivity of the RFID reader is an important parameter, which depends on the signal phase, frequency (BLF) and antenna gain and other values. A frequent 6db change means losing half of the range.