Optimal signal selection and rectenna design challenges for electromagnetic energy harvesting and wireless power transfer

Signal and circuit design leading to improved rectifier efficiency is discussed. First, the use of time varying envelope signals such as modulated, white noise and chaotic signals as potential candidates leading to optimum rectifier RF-DC conversion efficiency performance is presented. Second, the limitation of rectifier design at a given input power and load conditions is highlighted and the use of resistance compression networks to reduce the sensitivity of the rectifier RF-DC conversion efficiency with the load impedance and input power variation is demonstrated.