Microwave Dielectric Sensing for Sample Preparation in Digital Microfluidics

摘要

This paper reports on uniplanar interdigital capacitors employed for dielectric sensing in digital microfluidics. Two interdigital capacitors on a microwave chip, a quadrature coupler and a phase shifter were used to build a tuneable 2-port network for glucose concentration extraction in glucose-DI water mixture using the interference principle. One capacitor in the setup was used as a sensor, while another capacitor was used as a reference. Microwave measurements were carried out at 4.5 GHz using the tuneable 2-port network for reference liquids being deionised water and a glucose-deionised water mixture. Measurement results demonstrated an accurate extraction up to 0.1 M glucose concentration.