Equivalent input and output impedances in HF RFID system including resonator

High Frequency Radio Frequency Identification (HF RFID) system based on Magnetically Coupled Reader Resonator Coils (MCRRC) is reported. The proposed system consists of reader antenna including small resonant coil operating by magnetic coupling with the tag coil. In the proposed system, the reader and tag impedances are modified. The equivalent electrical model is used to express the equivalent impedance matrix and used to express the equivalent input and output impedances of the system. The formulas are confirmed by comparison between High Frequency Structure Simulator (HFSS) results and measures.