A rectenna device (400) for converting incident light to electrical energy is disclosed. The rectenna device comprises a substrate (402), a first metallic layer (404) having a predefined thickness deposited on top of the substrate, a rectifying element (405) deposited on top of the first metallic layer, a second metallic layer (408) deposited on top of said rectifying element and configured to collect electromagnetic waves of the incident light and to couple it into plasmonic waves within the rectenna device, the second metallic layer comprising an array of a plurality of metallic patches (410) spaced from each other according to a predefined spacing, each metallic patch having predefined dimensions. The rectifying element is configured to rectify the plasmonic waves to produce a direct current, the plasmonic waves being generated at one or more operating wavelengths, and at least one dimensioning parameter of the rectenna device is determined from at least one operating wavelength, the at least one dimensioning parameter being chosen in a group comprising the dimensions of the plurality of metallic patches, the spacing of the metallic patches in the array, and the predefined thickness of the first metallic layer.