POSITION SENSING APPARATUS HAVING INTERNAL TARGET ROD WITH REMOTE ELECTRONICS FOR HARSH ENVIRONMENTS

A sensing apparatus that measures a target characteristic. The apparatus has a sensing element formed as a section of a coupled slow-wave structure including a hollow ceramic tube and at least two impedance conductors each curled into a helix with opposing directions of winding around the tube to form a resonator. The sensing element is connected by coaxial cables to a remote electronics module which includes electronic components to create a resonant circuit with the sensing element. A metal internal target rod is configured to move into and out of the sensing element, being covered and uncovered by portions of the sensing element. This will cause the frequency of the resonant circuit to change proportionally to the movement of the target rod. The length of the coaxial cables separates the electronics module from the sensing element by a distance sufficient to avoid exposing the electronics module to harsh environments.