Quasi-Lumped Coplanar Transmission-Line Sensors for Broadband Liquid Characterization

Quasi-lumped structures are used to develop two sensors based on coplanar waveguide transmission lines. The broadband sensors are fabricated using microsystems technology and are used between 1 and 35 GHz. A calibration method to determine the sample permittivity is adapted. The sensors are intended for the non-invasive characterization of biological cells. Saline solutions, water, and an ethanol-water mixture are used to experimentally verify the functionality of the sensors for this purpose. The simulated sensitivity of a quasi-lumped sensor is shown to be up to seven times higher than that of a conventional coplanar waveguide sensor. This hints at the miniaturization potential of these sensors.