A current-driven RFID reader with automatic antenna tuning

RFID systems that automate most involved procedures including maintenance are in higher demand. One maintenance procedure is the periodic adjustment of the tuning of the antenna circuit. In the first part we analyze the reasons for an accurate tuning insisting on its influence on the decoding of the signal received from the tag, with reference to voltage-driven and current-driven readers. In the second part we present an automated solution for tuning that makes use of a Xilinx programmable logic device and has been applied to a current-driven reader produced by Frosch Electronics.