This paper proposes an analytical, closed-form AC-DC voltage multiplier model and investigates the dependency of output current and input power on circuit and device parameters. The model uses no fitting parameters and a frequency term applicable to both multipliers using diodes and metal-oxide semiconductor field effect transistors (MOSFETs). Analysis enables circuit designers to estimate circuit parameters, such as the number of stages and capacitance per stages, and device parameters such as saturation current (in the case of diodes) or transconductance (in the case of MOSFETs). Comparisons of the proposed model with SPICE simulation results as well as other models are also provided for validation. In addition, design optimizations and the impact of AC power source impedance on output power are also investigated.

A rectifying antenna is one of the most important components for wireless power transmission applications. In our previous papers, some RF-DC conversion circuits with high conversion efficiency at low input power are proposed. However, these RF-DC conversion circuits have some parts of which size depends on operating frequency, so the circuit size becomes large at low operating frequency. And, the composition of these RF-DC conversion circuits is complicated. Therefore, in this paper, a new RF-DC conversion circuit composed of only chip devices is proposed. This circuit has higher conversion efficiency than the previously proposed circuits. And, size reduction of the RF-DC conversion circuit is realized. Moreover, the composition of the circuit is simple, so the circuit size does not depend on operating frequency. For design of the RF-DC conversion circuits, LE-FDTD method is used. The measurement results agree with analytical results of the LE-FDTD method very well, and availability of the LE-FDTD method is discovered. It is shown that LE-FDTD method is a powerful analytical way which can give efficient design of RF-DC conversion circuit with high conversion efficiency.