A Dielectric Permittivity Sensor Based on Inverted Microstrip/3D-Printing Hybrid Technology

The paper reports on the development of an innovative sensor for the dielectric characterization of liquid materials. The sensor is based on a section of inverted microstrip line with a quarter wavelength open ended stub, combined with a channel where the liquid material flows. The structure is fabricated by using a hybrid technology, which integrates the standard printed circuit board technique (to implement the inverted microstrip) with additive manufacturing (to realize the channel and the support structure). The dielectric characteristics of the liquid material can be retrieved from the variation of the frequency response of the structure (with respect to the case of no liquid). Different liquid materials are adopted for validating the performance of the fabricated component, comparing simulations and measurements.