Strain omnidirectional detection based on circular patch antenna

[Display omitted] •A wireless omnidirectional strain detection method based on circular patch antenna is proposed.•A circular patch antenna is used to detect the magnitude and direction of the structural strain.•The linear relationship between the resonant frequency shift of the circular patch antenna and the strain is extracted. In this research, a circular patch antenna is proposed for omnidirectional measurement of strains. Firstly, the interaction between the circular patch antenna and the strain is analyzed according to the cavity theory in electromagnetic waves. The resonant frequency is determined by the size of the patch antenna. While a strain is applied, the dimension of the patch antenna changes slightly. Then, the linear relationship between the frequency shift and the strain is obtained. The strain sensor based on circular patch antenna is fabricated to measure the strain in different direction. A microwave wireless detection system is established to detect the magnitude and direction of the structural strain. The experimental result is in good agreement with the strain gauge. It shows that the circular patch antenna is able to detect the structural strain omnidirectional and wireless, which lays a foundation for the further engineering applications.