Miniature Broadband Vibration Transducer Design Fractal Structure

With the rapid development of the low power and independent operation of the system,such aswireless sensor networks,embedded intelligence structures and wearable health monitoring etc,theneed for a long life and separate power supply technology more and more intense.Mechanicalenergy is the energy of a wide range of forms,and it’s also present in areas of difficult to access,themicro vibration transducer is a broadband access to a means for energy vibrational energy.In this thesis, a vibration transducer fractal structure designed to solve narrow bandwidth andlower energy density problems. In order to solve these two problems， designs a newstructure-fractal structure.Fractal structure has irregular and self-similar characteristics, it has manyirregularities inherent frequency,so it can always be in a steady stream to collect environmentalvibration energy in a wide spectral range; self-similarity make it have more approximating thenatural frequency, it can produce more energy output when the resonance condition is satisfied; thusit solves the vibration transducer bandwidth is narrow and low energy density problem.In this paper,the fractal structure basis on the polyvinylidene fluoride (PVDF) piezoelectricfilm and the cantilever.By comparing the different characteristics of the piezoelectric material tochoose the PVDF piezoelectric film as a piezoelectric material;by analysising the cantilever withmass block and the cantilever not with mass block to laid the theoretical foundation of fractalstructure.According to peano fractal characteristics, design model peano fractal structure, and baseon a graph of frequency and frequency number re-optimize the peano fractal model design.Byanalyzing the frequency characteristics and electrical properties of peano fractal model to get a lotof data and graphics,validate the fractal model’s large bandwidth and high energy densitycharacteristics on theory.Using the finite element of COMSOL Multiphysics to build the model offractal structure.Finally, the paper gives the process of establishing experimental platform, including the PVDFpiezoelectric film micromachining and packaging, as well as signal transmitter circuit and anoscilloscope to build, test peano fractal structure laid the experimental ideas.