All around us, energy currently goes to waste. At any given moment, billions of Wi-Fi antennas and TV and radio stations are filling the atmosphere with electromagnetic waves. By harvesting these waves and converting them into electricity, we could tap into a vast source of “free” energy. 

The question is how.

WISE member Omar Ramahi, a professor in Waterloo’s Department of Electrical and Computer Engineering, is exploring the potential of frequency-selective surfaces (FSSs). Essentially, these…