However, the components of the circ

However, the components of the circuit for EH in a real system are non-linear. Owing to the non-linearity of the diodes, inductors and capacitors, the energy conversion efficiency is actually not a constant value, in general, for low power, the output power improves as the input power rises, but there are diminishing returns and limitations on the maximum possible harvested energy. That is, the practical EH circuit has the characteristics of sensitivity and saturation. Thus, the traditional linear energy harvesting model can not capture the non-linearity of the practical circuit, which is obviously lack of practicability