Integrated design of RF energy harvesting systems and converters for wearable and implantable microsystems

A CAD solution is proposed combining EM theory, full-wave numerical analysis, and nonlinear circuit techniques into an integrated numerical tool for the RF/base-band co-simulation and co-design of RF/microwave harvester systems operating in a multiband environment. Electromagnetic theory and software tools typical of an RF design environment, such as harmonic balance, are used to rigorously analyse the receiving antenna subject to multiple incident fields and loaded by the rectifier, and to design the antenna-rectifier interstage network. The results provide guidelines to be followed in the design of the baseband portion of the system. A novel boost converter circuit allows the rectified energy to be transferred to a storage capacitor in an optimal way, i.e., keeping the rectifier dynamically close to the load situation providing maximum rectified power. The overall result is very general, allowing harvester performance to be accurately described in virtually any practical humanized scenario. This includes those situations where the radiating element locations may be critical, such as in the vicinity of radio base stations. Design results and prototypes are demonstrated for multilayer configuration making use of textiles and flexible substrates whose integration issues are also accomplished.