All Polarization Receiving Rectenna With Harmonic Rejection Property for Wireless Power Transmission

In this paper, a high conversion efficiency rectenna for wireless power transmission at 2.45 GHz is proposed. The rectenna is fabricated on a low-cost FR-4 substrate. The proposed design contains a dual circularly polarized patch antenna in which a high-order harmonic rejection property is embedded, and a pair of rectifying circuits without harmonic rejection filters. The dimension for the proposed rectenna design is 100×100×3.8 mm
³
. The proposed rectenna collects waves in all polarization senses simultaneously with a suitable air gap width, chosen to maximize antenna gain, and provide high isolation between the rectifying circuits. The rectifying circuits are fed by the wave power of orthogonally polarized waves. The conversion efficiency is improved by blocking the second and the third harmonic noise from reemission without suffering loss from filters: the second harmonic noise is rejected with a T-shape slot, while the third is rejected by a U-shape resonator. The measured conversion efficiency of the proposed rectenna reaches 82.3% when the inputs of the rectifying circuits are fed at 22 dBm, surpassing the majority of existing rectenna designs in the current literature. The functionality of reception at all polarizations is also verified, distinguishing our design from other proposals.