Enhanced RFID tag detection accuracy using distributed antenna arrays

Abstract

An Ultra High Frequency (UHF) Radio Frequency Identification (RFID) system using distributed antenna arrays for interrogating RFID tags in a highly multipath environment is demonstrated. The system makes use of phase diversity and beam steering to overcome fading. The tag detection accuracy is compared to a standard fixed antenna system, showing that the presented system is able to deliver more power to the more challenging tags, and therefore is capable of a higher tag read success rate. It is also shown that, whereas a fixed antenna is capable of scanning a single cell, the ability of a phased array to scan through 360° azimuth leads to a reduction in number of antennas required for a multicell system. The experimental results are validated using a 3D field-based propagation model, which enables visualisation of the power distribution in the field of interest, and provides insight into the improved system performance.

Channel Inversion Method for Optimum Power Delivery in RF Harvesting Backscatter Systems

“…As a result, many techniques have been proposed in the literature to enhance the power delivery to tags. Among those techniques, some focus on developing novel beam-scanning antennas to enhance the system coverage by steering the antenna beam to different directions [9]- [11]; some work in [12], [13] attempts to achieve a wide-area coverage through the usage of a distributed antenna system (DAS) combined with frequency and phase hopping. Those techniques have been successful in combating multi-path effects and are sufficient for improving the detection probability of conventional passive RFID tags.…”