Two-Dimensional Near-Field Localization of Active Tag in the NFC Frequency Range

This paper describes a method for determining the position of an active tag in the form of a flat spiral coil within a fixed plane. The position is analyzed using a five-channel planar receiver system composed of three resonant coils. Signal amplitude values are used as the initial information parameters. The ability to identify the position arises from the unique mode structure of the field generated by the coils. Numerical calculations of the field distribution of the coils are performed, and the system's sensitivity to tag movement is evaluated. The examined coil system and the data processing technique enable two-dimensional spatial localization of the signal source, which can be applied in practical applications based on RFID technology.