Multi-domain design of wearable energy generators harvesting from ambient RF sources

We overview a multi-domain CAD approach to the design of RF Harvesting systems and dynamic converters which need be followed for systems harvesting ultra-low RF power densities. In real operating conditions such systems are required to dynamically adapt themselves to variable workload conditions to track voltage levels while conserving energy. This points out the key difficulty in the simulation and design of this class of systems which need be concurrently carried out from RF (antenna and rectifier) to base-band (optimum loading conditions). At RF, the subsystem consisting of the receiving antenna, loaded by the rectifier and of the antenna-rectifier inter-stage network need be designed in steady-state nonlinear. At baseband the transient design of a DC-DC converter, keeping the rectifier dynamically close to the optimum load condition, is designed by transient analysis. The whole procedure is applied to a wearable multi-band rectenna with simultaneous specification on ports isolation, radiation efficiency and converted DC power.