Self-Sustainable Magnetoelectric Smart Sensors

Conventional sensors for magnetic field, electric current, and rotational speed measurements are best represented by Hall and reluctance devices. Hall devices need to be powered by highly stable constant-current sources, and their inherently weak Hall voltages (5–50µ V/ Oe) impose great demand on external signal conditioners. Reluctance devices require being interfaced with highly precise, low-noise, low-drift integrators, and real-time measurements are generally inhibited at low frequencies. Importantly, both types of sensors are not self-sustainable, leading to great complexity and cost ineffectiveness in applications.

A research team from the Department of Electrical Engineering of The Hong Kong Polytechnic University has developed a new generation of sensors to overcome the drawbacks intrinsic to conventional Hall and reluctance devices and their equivalents based on proprietary magnetoelectric composite materials. These innovative smart sensors require no external power supply to sustain their operations, and produce significantly larger output voltages (>100 mV/Oe), typically over 2000 times higher than the Hall voltages. These sensors are very simple; each of them is essentially a single, passive, solid-state magnetoelectric composite element with housing. These attractive features/characteristics make the sensors to be more cost-effective, reliable, and suitable for a broad domain of applications