Inkjet-Printed Smart Skins and Wirelessly-Powered Sensors for Wearable Applications

This chapter discusses the design and fabrication process of inkjet-printed smart skins and wireless sensors. Complex multilayer structures can be implemented by stacking printed layers of conductive and dielectric inks, and sensing modules can be fabricated using nanomaterials such as graphene oxide and carbon nanotubes (CNTs). Microfluidic-tunable filters and antennas can be fabricated without the need of clean-room or chemical treatment, significantly reducing the manufacturing cost of such devices. The feasibility of making fully flexible circuits and sensors has been clearly demonstrated by either printing conductors or inkjet-printing detailed low-cost masks followed by simple etching techniques. Inkjet printing also facilitates the fabrication of structures for demanding scenarios such as microfludic sensors for biochemical applications. Finally, the easy realization of inkjet-printed energy harvesting circuits on flexible materials could potentially allow the full powering of microcontrollers and sensor circuitry, which would be necessary for the realization of truly autonomous wearable wireless systems for Internet of Things applications.