During the final phase, work advanced successfully across all technical and management work packages, culminating in the full demonstration of the MetaVEH concept — autonomous, lead-free vibration energy harvesters enhanced by metamaterial architectures and nonlinear circuits. Despite early pandemic challenges, coordination remained strong, leading to validated prototypes at both macro and micro scales.
WP1–WP2 (Coordination, Dissemination, and Management):
Project management continued smoothly after coordination transferred from ETH Zürich to ZHAW. The project website (www.metaveh.com) was regularly updated with publications and outreach materials. Dissemination was extensive: over 25 journal papers, 30+ conference presentations, and two international workshops (BOHEME–METAVEH 2023 and Euromech 649, London 2024). Outreach included Il Sole 24 Ore, the Waves – Dive In! exhibition at ETH Zürich, and Open Days at Politecnico di Milano.
WP3 (Mathematical and Numerical Tools):
New modelling and simulation frameworks were developed for graded and nonlinear metamaterials, combining Bloch–Floquet theory and nonlinear dynamics. These models guided the design of both macro- and micro-scale prototypes and enabled prediction of broadband energy-harvesting behaviour.
WP4 (Macrofabrication):
Binder-jetting 3D printing and laser micro-machining produced complex lead-free piezoelectric metastructures (KNN) and diode-less rectifiers capable of broadband energy collection. Laboratory tests at ETH and ZHAW validated wideband performance (5–500 Hz) and led to the creation of the EMetaNode prototype — a compact autonomous harvester integrating mechanical, electronic, and wireless subsystems.
WP5 (MEMS Meta-harvester Fabrication):
MEMS prototypes based on AlN and AlScN thin films achieved high-Q resonant modes, enabling both micro-harvesting and RF filtering. A novel on-chip characterisation method for piezoelectric properties was demonstrated, improving MEMS design efficiency.
WP6 (Testing and Benchmarking):
A new dynamic test bench simulated infinite waveguides under realistic vibration conditions. Testing of nonlinear and contact-based harvesters confirmed that the EMetaNode can power IoT sensors for several days from ambient vibrations, achieving TRL 5.
WP7 (Integration and Exploitation):
The final integration combined low-power firmware (written in Rust) with LoRa-based data transmission and cloud connectivity. Deliverables D7.1–D7.2 defined the marketing and business plan and engaged industrial partners (Multiwave, Kistler, Irmos) through Letters of Intent and pilot assessments.
The Innovation Radar exercise (June 2025) identified six key innovations, including three flagship results:
Portable vibration energy harvesters for space- and time-sparse sensing (EMetaNode);
Contact-based meta-actuators for adaptive vibration control;
Magnetic frequency up-conversion for broadband harvesting.
Overall, MetaVEH achieved all its objectives, moving from concept (TRL 2–3) to validated prototypes (TRL 5). The project proved that sustainable materials, metamaterial design, and efficient electronics can converge into a single, battery-free platform — a key step toward self-powered smart infrastructure and IoT systems.
