New methodology for the short range localization of UHF RFID tags using a linear uniform array

This paper describes a new methodology and an experimental setup to localize UHF RFID (UltraHigh Frequency Radio Frequency IDentification) tags with a linear antenna array connected to a RFID reader. The operation is effective in the array Near-Field (NF), i.e., for short range localization where both the distance and azimuth can be estimated. An estimation method much less complex and as performing as the two dimensional Multiple Signal Classification (2D-MUSIC) method and High-Order Propagator Method (HOP) is described. The proposed method is based on second order statistics and it has a good accuracy and low complexity without Eigen value decomposition (EVD) of the covariance matrix. We claim that it achieves good accuracy and low complexity. An array calibration technique is applied to take into account the phase variation of the received signal at each array element. The effectiveness of our method is proved analytically and experimentally for a 3-element array and 4-element array.