Sensing Using Magnetoinductive Waves

The propagation of slow magnetoinductive (MI) waves by virtue of magnetic coupling between resonant elements (called meta-atoms in the terminology of MI waves) enables applications ranging from improved medical imaging to wireless power transfer. A recent development is the use of MI waves in contactless sensing of conductive environments, both in the frequency and in the time domain. The underlying physics in both methods is that a perturbation due to the presence of a conductive object in the vicinity of a meta-atom changes resonant characteristics of the meta-atom and causes reflections of MI waves within the array. In this chapter we focus on time-domain reflectometry, demonstrating accurate defect localisation and characterisation. We discuss potential applications for real-time contactless monitoring of inhomogeneous conductive environments ranging from in-situ 3D printing quality monitoring to medical imaging.