Far-field MEMS microphone array beamforming – Measurements, simulations, and design

This thesis work determines the far-field array response patterns of micro-electromechanical system (MEMS) microphone arrays; and verifies these patterns employing experimental methods. Phase shifts and amplitude behaviour are simulated through finite element methods (FEM) using COMSOL Multiphysics, under both ideal and realistic conditions. Physical measurements are performed with microphone arrays using high accuracy audio analyzer equipment (Audio Precision APX555) to support and compare with mathematical and simulation conclusions. The effects of the packaging, mounting materials, and interference among elements on the array response patterns are studied using two-element microphone arrays. A new form of MEMS microphone array beamformer – a dynamic layout array beamformer – is introduced and simulated with the goals of improving flexibility, while lowering the complexity and power consumption, of MEMS microphone array systems. In addition to the acoustic signal recognition, a new approach is developed with a Xilinx Basys3 FPGA board to record and analyze the audio files using PmodMIC3 MEMS microphone devices. Applications based on the MEMS microphone array beamforming are introduced. Potential applications of the research to intelligent transportation system (ITS) moving vehicle direction of arrival (DOA) estimation are presented for further study.