Systems and methods for an improved solar/infrared conversion efficiency using multiple rectennas, one for each band of the spectrum. Each rectenna is optimally efficient for each spectrum band. An antenna receives at least one of a visible or infrared spectrum. Rectifying circuits coupled to the antenna generate a current based on a portion of the spectrum received by the at least one antenna. Each rectenna operates efficiently using a different operating voltage. The operating voltages are based on the selected load resistor and the current-voltage characteristics for the diode of the rectifying circuit at the associated spectrum portion.