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 rec-
tifying circuits without harmonic rejection filters. The dimension
for the proposed rectenna design ismm . The
proposed rectenna collects waves in all polarization senses simulta-
neously 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 polar-
ized waves. The conversion efficiency is improved by blocking the
second and the third harmonic noise from reemission without suf-
fering 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.