A Newly Developed Radio Frequency Wireless Passive Highly Sensitive Strain Transducer

A novel design of a highly sensitive wireless passive radio frequency strain transducer is presented based on a patch antenna loaded with an open loop that is capable of sensing strain remotely. The new idea of utilizing a cantilever at the gap of the open loop significantly improves the sensitivity of resonant frequency shifts. In measurements, the prototypes achieve a sensitivity of 1.26% frequency shift per 1% strain, while in simulations the new design achieves a theoretical sensitivity up to 4 times higher than existing designs of RF passive wireless strain transducers. The ground plane allows for the sensitivity of the sensor to be independent from the applied surface. An implementation example of the passive remote sensing system based on the proposed strain transducer is also discussed as a proof-of-concept.