A Miniaturised Linear Shaker System for MEMS Sensor Characterisation

摘要

A miniaturised, piezoelectrically driven shaker system is presented which is suitable for MEMS characterisation in vacuum. It offers a broad frequency and amplitude range. The fully vacuum compatible shaker is constructed out of one single peace of aluminium with a piezo-stack-actuator working in-plane against four beam springs. It can easily be fabricated at low costs using a hand operated milling machine. The systems characteristics are easily tuned to different applications as the first resonance frequency is given by the stiffness of the beam springs and the mass of the moving shaker table. The utilised piezoelectric stack determines the maximum reachable amplitude for a given spring stiffness. Finite Element simulations have been carried out to design a flat transfer characteristic of the shaker up to 10 kHz and amplitudes in the range from sub nanometres up to 1 μm. The simulations were evaluated by laser vibrometer measurements of the shaker which also show a good linearity between electrical excitation signal and output deflection amplitude. To account for other resonance frequencies introduced by a preexisting MEMS mounting device, the resulting vibration amplitude on the MEMS structure can be normalised by adjusting the electrical excitation amplitude with the help of a Polytec laser vibrometer.