UHF RFID Tag Performance Evaluation based on Radar Cross Section

The passive ultra-high frequency (UHF) RFID is being increasingly employed in various applications. The low-cost, long range and high data rate features making it an outstanding choice in contactless identification. Although, passive tag performance is likely to be affected by water and metal, tag packages and special tag designs are developed to minimize the effect of the environment. Tag performance is often described in terms of the maximum read range. To further investigate the performance of the passive UHF tag, tag’s radar cross section (RCS) is analyzed. The RCS of a tag defines backscattering field strength of that tag; it is then an important parameter in determining the performance in tag-to-reader communication link. In addition, by using the knowledge of RCS, the bit error rate (BER) of the tag transmitted signal presented at the reader input terminal can be achieved and the stability in tag reading can be estimated. In this paper, the performance of a tag in various rotation angles with respect to the reader in terms of BER is evaluated. The RCS of each angle was determined by simulation and the BER was calculated based on the RCS information. We also measure the read rate to investigate the relationship between RCS, BER and the successful read rate in actual environment.