Displacement Sensitivity and Range Enhancement Through Buckled Beam-Assisted OE-HCCR

This article proposes an ultrasensitive and wide-range displacement sensor utilizing an open-ended hollow coaxial cable resonator (OE-HCCR) assisted by a buckled beam structure. The OE-HCCR comprises of two highly reflective reflectors including a metal post that shorts the inner and outer conductors, and the open end of a hollow coaxial cable. To achieve displacement transfer and amplification, a buckled beam combined with a diaphragm is utilized near the open end of OE-HCCR. When the sensor is subjected to displacement, the buckled beam is deformed thus introducing an axial movement, which is subsequently transferred and introduces an amplified deviation at the center of the buckled beam. Also, the gap distance variation between buckled beam and coaxial cable open end will lead to OE-HCCR’s resonant frequency change. Experimental results demonstrate that the prototype displacement sensor exhibits ultrahigh displacement sensitivity of up to 0.8175 MHz/mm, a measurement range of 2.0 cm, and a low-temperature cross sensitivity of 0.0014 mm/°C. With its advantages of high displacement sensitivity and wide range, low-temperature cross-sensitivity and enhanced robustness, the proposed displacement sensor can be considered as an excellent candidate for applications in the construction industry and intelligent manufacturing.