Modeling and influence of matching network insertion losses on ambient microwave power harvester

Matching network insertion losses have usually been overlooked in the development of microwave power harvesters (MPH), being assumed as an unavoidable inherent problem of matching networks. This paper makes use of a simple L-matching network to derive the optimum junction resistance of a rectifying diode and study the tradeoff between power conversion efficiency and matching network efficiency, in order to obtain the maximum total energy harvesting efficiency. Even though insertion losses are unavoidable, the need to find lower loss matching techniques is discussed, if the currently observed limitation of MPH-related microwave-to-DC power conversion efficiency is to be overcome.