Ultra-small energy harvesting microsystem for biomedical applications

Wireless power transfer using coupling in the near-field, in opposition to far-field, shows advantages concerning link efficiency, however the link performance is widely dependent on proper antenna positioning. The transmission of energy using a far-field link would be desirable in many applications, namely for powering biomedical devices placed inside the body. This paper presents results from a system that was designed to operate inside the human body and relies on a 3D antenna (500×500×500 μm
³
), fabricated using self-folding technology, operating in the low gigahertz range. Wireless power transmission and power conversion between 1 and 4 GHz were evaluated. Far-field wireless power transmission was demonstrated using the electrically small microantenna and a DC load of 1 kΩ.