Low power rectenna topologies for medium range wireless energy transfer

This paper presents and compares different rectifying antenna (rectenna) circuit topologies optimized for sub-mW incident microwave power levels. Excellent performance is achieved in terms of output voltage level and RF to DC conversion efficiency. Several prototypes have been fabricated using small localized components and tested. A detailed study of the behavior of a low power rectenna as a voltage source is presented. The influence of the antenna characteristic impedance on circuit performance is also studied.