Metasurface‐inspired maintenance‐free Internet of things tags characterised in both frequency and time domains

The authors present metasurface‐inspired maintenance‐free Internet of things (IoT) tags that can be characterised not only by frequency‐domain profiles but also by time‐domain profiles. In particular, time‐domain characterisation is made possible by implementing the waveform‐selective mechanisms of recently developed circuit‐based metasurfaces that behave differently, even at the same frequency, in accordance with the pulse duration of the incident wave. The proposed designs are numerically and experimentally validated and potentially contribute to accommodating an increasing number of IoT tags within a single wireless network while reducing maintenance effort. Proposed metasurface‐inspired maintenance‐free IoT tags are characterised not only in frequency domain but also in time domain. The use of both frequency‐ and time‐domain profiles enables us to increase the number of IoT tags accommodated within a single wireless network without replacement of batteries.