3D passive RFID tag over-the-air measurement

The knowledge of the three dimensional directivity of RFID tag antennas can help with the design and implementation RFID tags for various applications. Especially a careful choice of the tag position and orientation has the potential to improve the overall RFID system performance dramatically. The task is much easier to handle with the knowledge of the full 3D directivity of the passive RFID tag. This paper describes a setup and a method to measure the three dimensional directivity of passive RFID tags. A spherical nearfield scanner is used combined with additional RFID measurement equipment. The three dimensional measurement results of a standard RFID label are presented as well.