Near field scans of tyre mounted dipoles using a separate phase reference antenna

This paper reports on near field measurements of dipole antennas mounted inside a wheel for advanced tyre monitoring applications based on UHF RFID technology. We propose, implement and validate a near field measurement technique which avoids the need for any error prone feed cable. This technique is then used for measuring the patterns of two different dipole antennas attached to the inner surface of a tyre in four mounting configurations. Finally, the measured antenna patterns are discussed, as well as their implications for the channel characteristics when these dipoles are used.