Harmonic Reaction Inductive Folded Dipole Antenna for Direct Connection With Rectifier Diodes

In this paper, we present a harmonic reaction inductive folded dipole antenna (FDA) for a highly efficient rectenna which is close to the fundamental limitation on efficiency. To remove lossy RF circuit components of the rectifier, the proposed antenna topology integrates circuit functionalities for highly efficient rectification, such as impedance transformation to high-impedance, impedance matching, DC blocking, and harmonic reaction. The proposed antenna is connected directly to rectifier diodes. Thus, the rectification efficiency can be improved toward the fundamental limitation restricted by the performance of the rectifier diode. In experimental investigations of the 2.4 GHz band antenna, the antenna radiation efficiency is 99.2%, and the degradation due to integrated circuit functionalities is negligibly small. The 2.4 GHz band bridge rectifier achieves a rectification efficiency of 91.1% at an input power of 30 dBm. This clarifies the effectiveness of the efficiency improvement with the proposed direct connection topology between the proposed FDA and bridge diode.