A High-Resolution Reflective Microwave Planar Sensor for Sensing of Vanadium Electrolyte.

Microwave planar sensors employ conventional passive complementary split ring resonators (CSRR) as their sensitive region. In this work, a novel planar reflective sensor is introduced that deploys CSRRs as the front-end sensing element at fres=6 GHz with an extra loss-compensating negative resistance that restores the dissipated power in the sensor that is used in dielectric material characterization. It is shown that the S11 notch of -15 dB can be improved down to -40 dB without loss of sensitivity.