A wireless passive vibration sensing method for cryogenic applications

In this Letter, we developed a wireless passive vibration sensing method functional at cryogenic temperatures (−196 °C). Traditional vibration sensors are either inconvenient or complicated in cryogenic environments due to inaccessible working positions and weak low-temperature tolerances. We propose a vibration measurement method that transfers a mechanical vibration to a wirelessly obtained return loss. Passive wireless monitoring is performed using a backscattering tag antenna integrated with a tunnel magnetoresistor. We fabricate and evaluate our vibration sensor at room temperature (24 °C) and cryogenic temperature (−196 °C) to verify the proposed design. Experimental analysis identified different vibration amplitudes with sensitivities of 4.61 dB/mm at 24 °C and 1.13 dB/mm at −196 °C. Further analysis shows that the vibrational frequency can be extrapolated. Our sensor provides a low-cost, robust, wireless, and passive vibration measurement method that is desirable in cryogenic applications.