Energy Harvesting from Solar Short Wave Infrared Radiation

The Sun radiates randomly polarized infrared waves with a wavelength starts from 0.7 um. A bowtie antenna is designed using the CST Studio Suite. The antenna bandwidth extends from 200 to 350 THz (0.55 fractional bandwidth). This bandwidth enables the antenna to capture 200 W per meter square of power density. Power density from the Sun at the equator is 1000 W per meter square. The angular 3dB beamwidth is 140 degrees, which enables the antenna to capture energy coming from diverse directions and avoids using any tracking system. Since the bowtie antenna is linearly polarized, two crossed bowtie antennas are used to capture all incident energy. The distance between elements in the array is taken to be half a wavelength (0.5 um) to reduce mutual coupling. One square meter gives 142.8 W of harvested power. Exploration of suitable materials and fabrication techniques, and integration with conventional photovoltaic cells is a future work plan.