Piezoelectric Energy Generator

Device Structure:

• Geometry: Cantilever beam

• Layers (from bottom to top): SiO2, Silicon, Gold, PZT-5H

• Dimensions:

  • Width: 60 µm

  • Depth: 10 µm

  • Heights: Si (1.5 µm), Au (0.2 µm), SiO2 (0.1 µm), PZT-5H (0.5 µm)

Boundary Conditions:

• Fixed constraint applied at one end of the beam.

• Body load applied to simulate mechanical acceleration.

• Terminal assigned to top interface of PZT.

• Ground assigned to bottom interface of PZT.

Meshing:

• Fine mesh applied to ensure accuracy in deformation and field calculations.

Study Settings:

• Type: Stationary

• Parametric Sweep: Acceleration from 1g to 5g, Load Resistance R_load = 1kΩ to 5kΩ

Simulation Outputs:

1. Eigenfrequency: 1.9002 MHz

2. Displacement:

   • Maximum at the free end

   • Increases with g-force

3. Stress (von Mises):

   • Peaks near the fixed end

   • Highest at 5g (~265 N/m²)

4. Electric Potential:

   • Uniform along the beam

   • Becomes more negative with g-force

   • Negative due to compressive strain opposing poling direction

5. Electric Energy:

   • Constant across beam

   • Increases with g-force

   • 5g: ~1.05 × 10⁻²⁴ J

Applications:

• IoT Sensors

• Wearable Devices

• Medical Implants

• Structural Health Monitoring

• Aerospace and Industrial Systems

Conclusion: The MEMS-based piezoelectric energy harvester efficiently converts mechanical energy from vibrations into electrical energy. The simulation confirms mechanical reliability and electrical performance, making it suitable for autonomous low-power systems.

References:

• COMSOL documentation and MEMS module references

• Research articles on piezoelectric cantilever beam harvesters (listed in project report)

Note: All parameters are based on simulation results performed using COMSOL Multiphysics 5.2a with a 12th Gen Intel Core i5-1240P system.