Design of Highly Efficient and Compact RF-DC Conversion Circuit at mW-class by LE-FDTD Method

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.