Fabrication and modeling of a capacitor microfluidically tuned by water

International audienceThis letter presents the fabrication and the modeling of a continuously tuned microfluidic capacitor. On one hand its electrodes are realized by classical electrodeposition techniques and on the other hand, the lamination of SU-8 films allows superposing some microfluidic channels. According to the experimental results, the capacitor value increases continuously following the deionized (DI) water penetration in microchannels. The capacitance variations are comprised between Cmin = 0.52 pF and Cmax = 18.5 pF, allowing a wide tuning range that reaches 3460% at 500 MHz. The quality factor decreases from Qmax = 69 when the capacitor is empty to Qmin = 5.3 when it is fully filled with DI water. We have also investigated the theoretical aspects of our device by modeling the electric field and the current distributions inside the channels: when they are entirely filled with the DI water, the electric field is cancelled