We propose a concept for true wide bandwidth vibration energy harvesting. Our approach exploits nonlinear stretching of fixed-fixed beams in an off-resonance mode, effectively expanding the operational frequency range well beyond the narrow bandwidth of linear resonators. Our initial prototype demonstrates operation between 160–400 Hz, without the need for frequency tuning. A simple dynamic model shows good agreement with measurements. Optimized device geometry will allow for even lower frequency operation (starting at 60 Hz) at strain levels above 1e-3 (ideal for piezoelectric transduction).

We experimentally demonstrate a true wide bandwidth vibration energy harvester based on piezoelectric transduction. Our device is designed to work specifically off-resonance under sinusoidal input vibrations with constant displacement amplitudes. The same device displays wide bandwidth operation under vibrations with constant acceleration amplitudes. We have achieved over 6 nW of wide bandwidth power extraction per active piezoelectric patch between 80–180 Hz for constant 100 µm displacement amplitude, and across 20–90 Hz for constant 3g acceleration amplitude. Simulation of the micro-harvester with optimally fabricated piezoelectric material demonstrates over 1 µW of power across the same frequencies, enabling a fully integrated, self-powered wireless sensor node.

We propose a microsystem integration technique that is ideal for low-cost fabrication of vibration energy harvesting sensor nodes. Our approach exploits diverse uses of sol-gel deposited lead zirconate titanate, effectively combining fabrication of several microsystem components into a single process and significantly reducing manufacturing cost and time. Here, we measure and characterize thin film parameters—such as the piezoelectric coefficient e31 (−4.0 C/m2), the dielectric constant εr-eff (219 at 3.3 V), and the total switching polarization (2Pr;52 μC/cm2)—in order to verify this material’s potential for energy harvesting, energy storage, and nonvolatile memory applications simultaneously on the same device.

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