Wireless strain measurement using circular microstrip patch antennas

Wireless interrogation of circular microstrip patch antennas (CMPAs) for strain sensing is investigated by experimental measurements and computational simulations. The effect of the conductivity of the host structure on the wireless monitoring efficiency is also considered. It is shown that strain can be measured wirelessly in any desired direction using a linearly polarised horn antenna, up to a distance of 5 cm. Beyond this distance, the signal-to-noise ratio diminishes for the CMPAs employed in this study. This new contactless strain sensing technique offers significant potential for wireless structural health monitoring of civil and aerospace structures.