Wide-range displacement sensor based on a hollow coaxial cable Fabry-Perot resonator

摘要

This paper reports a novel hollow coaxial cable Fabry-Perot resonator for wide-range displacement measurements, up to meter range. The sensor is based on a novel and homemade sensing platform, hollow coaxial cable, in which the traditional insulating layer is replaced by air. The diameter of the inner conductor and outer conductor of the hollow coaxial cable are designed to be 6 mm and 14 mm respectively, to achieve an impedance of 50 Ohm. Two highly reflective reflectors, including a fixed one and a movable one, are engineered on a hollow coaxial cable to form a Fabry-Perot resonator (HCC-FPR). A measurement handgrip is permanently connected to the second reflector. Based on this design, the displacement of the measurement handgrip can be transferred to the cavity length change of the HCC-FPR. The change in the cavity length can be determined by tracking the shift in the reflection spectrum. The physics of the sensor was described, and the displacement response of the sensor was tested.