A novel capacitive receiver of an ultrasonic proximeter enhanced by PDMS gap

Abstract

This study introduces an innovative capacitive receiver designed for an ultrasonic micro-proximeter, wherein the amplification of sensitivity is achieved by filling the gap between electrodes with polydimethylsiloxane (PDMS). It is postulated that the PDMS includes pores, which could contribute to a further increase in sensitivity. The analysis encompasses the simulation of a circular microplate subjected simultaneously to electrostatic, resistive foundation, and reflected acoustic wave pressures, considering the nonlinear mid-plane deformation of the plate. The dielectric constant of the medium within the gap, dependent on displacement, as well as the elasticity modulus of the gap medium, have been formulated and incorporated into the governing equation. A numerical method based on Galerkin's approach was utilized to solve the governing nonlinear equation. The outcomes illustrate the effectiveness of the proposed model in reducing the necessary voltage and improving the sensitivity of the system. It has been shown that the initial porosity of PDMS leads to a change in capacitance that is over five times larger compared to a scenario without porosity. The findings suggest that the proposed system displays heightened sensitivity at decreased levels of acoustic pressure. The model and findings presented here can be extended to other capacitive sensors necessitating enhanced sensitivity.