Design of passive wireless antenna sensors for strain measurement

Metallic dampers in the bridge structures will suffer from a certain degree of deformation leading to a damage or destruction. To assess the deformation of metallic dampers and to decide whether to replace, a passive wireless strain sensor is needed. In this paper, we propose a scheme to design the passive wireless strain measurement system. We first investigate the possibility that a folded patch antenna is used as a strain sensor and then design such a folded patch antenna with a coaxial line feed. We establish a model for the antenna by using the HFSS and perform a series of simulations to find the relationship between the mechanical deformation of antenna and its resonance frequency. With the relationship, the deformation of metallic dampers can be predicted by measuring the resonance frequency shift of the antenna.