Researchers from the University of Waterloo in Canada have discovered a new way to harvest electromagnetic energy using metamaterials instead of traditional antennas. Their work demonstrates for the first time the “full absorption concept,” proving that it is possible to collect all of the electromagnetic energy that falls onto a surface. The design doesn’t reflect or transmit any power, which enables full absorption of incident waves.
Instead of using classical dipole patch antennas, the new technology uses metasurfaces that are formed by etching patterns of shapes onto the surface of a material. Fine tuning the patterns can lead to much better energy absorption. The energy is channeled into a load through a conducting path that connects the metasurface to a ground plane, rather than having the energy dissipate in the material. This process results in much higher energy absorption than classical antennas, and reduces the size of the surface needed in order to harvest the energy.
The work is published in the journal Applied Physics Letters, and the team is now extending their research to infrared and visible spectra. The researchers envision the technology being used in a broad range of applications to help meet growing global energy needs. For example, the full absorption concept could applied to wireless power transfer in remote RFID devices. It could also be integrated into emerging clean energy systems such as space solar power, which gathers energy from sunlight in space and transmits it wirelessly to Earth.
