Design and Analysis of Hexagonal Dipole Nano-Rectenna Based on MIIM Diode for Solar Energy Harvesting

In this work, new design of hexagonal dipole nano-rectenna for solar energy harvesting is presented. The proposed design is composed of silver hexagonal nano-dipole antenna integrated with metal insulator metal (MIM) tunnel diode with single and double insulators. The proposed hexagonal nano-dipole antenna consists of two identical elements separated apart by air gap. The MIM tunnel diode is realized by overlapping the nano-antenna (NA) arms and sandwiching metal oxide layer in between to benefit from the high localized fields at the NA gap. The reported design performance in terms of the total radiation efficiency, directivity and total harvesting efficiency is studied. The numerical study of NA is carried out in the wavelength range 300-3000 nm, using the finite integral technique (FIT) method. The reported design has an average total radiation efficiency of 92.28% in the wavelength of range (300-3000) nm. The proposed NA with single insulator MIM diode, and double insulator, MIIM diode, give roughly the same results of maximum radiation efficiency of 98%, maximum directivity of 14 at the wavelength of 500 nm and total harvesting efficiency of 95.35%. These results are attributed to the sharp tips of hexagonal arms. Furthermore, MIIM diode offers zero bias voltage responsivity of 17.29 A/W and maximum responsivity of -170.9 A/W. This enhancement is due to the use of multi-insulators between the two metals.