Sensitivity Optimization of Microfluidic Capacitance Sensors

S. Satti[1], M. Baghini[1]
[1]Indian Institute of Technology Bombay, Mumbai, Maharashtra, India

As a part of a lab-on-chip-device, more often it is required to measure dielectric constant of the fluid. For this purpose it is necessary to develop a sensor whose size is compatible with microfluidic channel.

The work, presented in this paper, studies effect of the parameters influencing sensitivity of such a sensor and ultimately optimizes these dimensions to maximize the sensitivity. We have shown that the dependence of the figure of merit on certain parameters is not monotonic. Given certain constraints, such as an already existing microfluidic channel in PDMS, we can design electrodes that will maximize the sensitivity, i.e. change in the capacitor due to change in the dielectric constant of fluid flowing in the channel.