Accurate electric field measurement plays a crucial role in various fields, such as weather forecasting, industrial process control, and the safety of workers handling high-voltage cables. However, achieving precise measurements is technically challenging. A breakthrough has been made by a research team from the Technical University of Vienna (TU Wien), who have developed a silicon-based MEMS electric field sensor that overcomes traditional limitations. In collaboration with the Institute of Integrated Sensor Systems at Danube University Krems, this innovative sensor avoids interfering with the electric field it measures, making it more accurate and reliable. The study was recently published in the journal Nature Electronics.
Current electric field measuring devices often suffer from significant drawbacks. According to Andreas Kainz from TU Wien's Sensor and Actuator Systems Institute, these devices typically include conductive components that can distort the very electric field they are trying to measure. If grounding is required for reference, the interference becomes even worse. This makes them inefficient and difficult to transport. In contrast, the new MEMS sensor is made entirely of silicon and operates on a simple yet effective principle: a tiny spring connected to a micromesh-like structure that detects minute movements. When exposed to an electric field, the silicon structure experiences a force that causes the spring to stretch or compress slightly.
The sensor works by measuring the displacement of a mass suspended on an elastic element, which is fixed within a conductive frame. When placed in an electric field, electrostatic forces cause the mass to move, and this movement is detected using optical methods. A light source, such as an LED, shines through a grid-like silicon structure. The upper and lower layers of the mesh are precisely aligned so that, under normal conditions, no light passes through. However, when the electric field causes displacement, a gap forms between the layers, allowing light to pass through and reach a photodetector below. By analyzing the amount of light received, the strength of the electric field can be accurately calculated.
The prototype demonstrates impressive accuracy, capable of measuring electric field intensity from low frequencies up to 1 kHz. Although it does not detect the direction of the field, it can reliably measure weak fields as low as 200 volts per meter. "Our system is already comparable to existing solutions," says Andreas Kainz, "but our sensors are smaller and simpler." He adds that the technology still has great potential for further improvement. While other methods are well-established, this MEMS-based approach is still in its early stages. As research continues, it is expected to become even more advanced and widely applicable in the future.
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