Chipless RFID Multi-Reader System Utilizing Spatial Diversity and Combining Techique

Main objective of this paper is to enhance the detection performance of chipless Radio Frequency Identification (RFID) system in real environment considering multipath channels and realistic scenarios. A novel distributed multireader system utilizing spatial diversity and applying Calibration Equalization Method (CEM) followed by combining techniques is introduced. In this work, four readers are randomly distributed in a dense multipath channel in an indoor environment, where the deterministic channels between transmitters and receivers are simulated using ray-tracing tool considering the Radar Cross Section (RCS) of the emerged chipless RFID tag, environmental effects, multipath components and frequency dependence. A new multiplicative combining technique is illustrated and evaluated with the selective and equal-gain combining methods, where the multiplicative approach demonstrates superior performance and increases the depth of the tag notches with a factor of ten compared with the other combining methods. This leads to a signficant enhancement of the detection capability of chipless RFID tags in various complex scenarios and real applications.