Fig. 1. Block diagram of nanorectenna and load

Fig. 2. Results comparison between FDTD method and MOM result

Fig. 3. Three-dimensional structure of the spiral nanoantenna

Fig. 4. Radiation efficiency of the spiral nanoantenna with different numbers of ring as a function of wavelength and the total efficiency of the nanoantenna

Fig. 5. Radiation efficiency of the spiral nanoantenna with different widths of arm as a function of wavelength and the total efficiency of the nanoantenna

Fig. 6. Radiation efficiency of the spiral nanoantenna with different heights of arm as a function of wavelength and the total efficiency of the nanoantenna

Fig. 7. Three-dimensional spiral nanoantenna with substrate

Fig. 8. Radiation efficiency of the spiral nanoantenna with different substrate thicknesses as a function of wavelength and the total efficiency of the nanoantenna

Fig. 9. Absorption of spiral nanoantenna to sunlight with different wavelengths

Fig. 10. Response of spiral nanoantenna at different polarization directions

Fig. 11. Electric field distribution of the spiral nanoantenna at λ=800 nm. (a) x axis-polarized; (b) 45° to x axis-polarized; (c) y axis-polarized