POSITION SENSING APPARATUS WITH REMOTE ELECTRONICS FOR HARSH ENVIRONMENTS

A sensing apparatus for use in harsh environments to measure a target characteristic. The apparatus has a sensing element formed as a section of a coupled slow-wave structure including at least two impedance conductors each curled into a helix with opposing directions of winding around a dielectric base to form a resonator. The sensing element provides as an output signal a digital frequency that depends on the value of the measured characteristic. A target tube moves over the sensing element, covering and uncovering portions of the sensing element. An electronics module receives the output signal and displays the measured characteristic. A separate coaxial cable is connected to each impedance conductor on one end and to the electronics module on the other end, with the length of the coaxial cables separating the electronics module from the sensing element by a distance sufficient to avoid exposing the electronics module to the harsh environments.