Dual-band metamaterial-inspired microwave sensor for liquid dielectric spectroscopy

In this paper, an open complementary split ring resonator (OCSRR)-loaded monopole antenna is used as a liquid sensor for discrimination of ethanol solvents with different concentrations. The resulting dual-band sensor is working at 2.45 GHz and 4.74 GHz and has been fabricated on the FR4 commercial substrate. The sensor part is integrated with the electronic parts including a voltage-controlled oscillator (VCO) and a zero-biased Schottky diode detector (SDD) allowing the sensor to be low cost and portable. The proposed sensor has been find capable to discriminate a wide range of dielectric variations for ethanol concentration detection.