A mathematical approach of a HF RFID multi loop antenna for metallic environments

The most important factors that may influence and affect the performance of HF RFID systems that use passive tags, consists in the effects of the metallic environments in the proximity of the antenna. In order to overcome a part of these issues, both the device antennas and their impedance matching units must be optimized. This paper presents a mathematical model that enables the identification of the optimal size of a multi loop HF RFID antenna that would encompass the coordinates of a given surface. The antenna has been mathematically modeled, simulated and tested for a specific situation when the metal plate is positioned in its close proximity.