Nowadays energy harvesting is a hot topic. The possibility to collect energy from environment otherwise wasted has been investigated by several research groups. Around us there is a lot of unused electromagnetic radiation emitted by electronic devices, wi-fi points, telecom transmitting antennas, and so on. This energy wandering in the air can be collected by suitable receiving antennas, built up also with inkjet technologies above paper. Recent achievements in the field gained in the Georgia Tech School of Electrical and Computer Engineering are discussed here.