New Design Ideas For Tdr-Based Liquid Level Detectors

This work suggests some new solutions to TDR-based liquid level detectors. A 3D-printed waveguide cylinder has been designed in order to increase the sensitivity of the level measurement. By wrapping the probing waveguide-pair around a cylinder, an inclination angle phi is introduced which increases the time-of-flight by a factor of 1/sin phi and hence the level resolution is increased (by the same factor). This work also illustrates how nanosecond pulses (for TDR systems) can be generated by applying a technique usually found in FIMs (Field Ion Microscopes). A time resolution of 2 ns/mm (of liquid level) is reported and a generic nanosecond pulse generator is demonstrated.