Analytical modeling and numerical investigation of a variable width piezoresistive multilayer polymer micro-cantilever air flow sensor

Abstract

ABSTRACT Measurement of air flow is a vital concern in diverse domains. Piezoresistive micro-cantilever-based air flow sensing is a promising research domain within MEMS technology due to its several advantages. Displacement, bending stress, sensitivity, resolution and stability are significant challenges in the design of this sensor. These parameters are also affected by the cantilever profile and its materials. Hence, the purpose of this study is to investigate the performance of a piezoresistive multilayer polymer variable width profile micro-cantilever structure and propose its materials, fabrication process flow, optimisation of geometric dimensions, piezoresistors placement and piezoresistors circuit connections to address challenges in the design. Methodical steps towards design optimisation of the proposed sensor under the applied pressure due to its interaction with air flow comprise preliminary approximation of geometrical dimensions through analytical models developed using Conjugate Beam and Rayleigh methods, subsequently, 3D modelling numerical simulation using the COMSOL Multiphysics FEM tool. It is observed that numerical simulation results agree with the results of analytical modelling. It is concluded that the proposed study contributes to the development of accurate analytical models and design optimisation of a low-cost and stable micro-cantilever-based air flow sensor that performs yet equally well compared to previously published designs in terms of sensitivity.