Wireless Micromachines

Wireless power: Putting microresonators on the move.

An antenna design that taps into electric fields across air gaps makes low-power, wireless biomedical implants more feasible. Micromechanical resonators are tiny, silicon-based cantilevers that, due to their sensitivity to high-frequency AC fields, are being targeted as the receiving elements in wireless power designs. Pritiraj Mohanty and his co-workers from Boston University, United States, now demonstrate that sandwiching a piezoelectric material between a silicon resonator and a low-profile antenna noticeably improves power generation and the transmission of wireless electricity. When the flat antenna picks up wireless electric fields, it produces a potential that strains the piezoelectric element and polarizes its electric charges. The resulting polarized field stimulates the micromechanical resonator with surprising efficiency and successfully charges from up to 90 cm away with only nanowatt-level excitations.

(Editorial Summary - Microsystems and Nanoengineering)

Read it here:
http://www.nature.com/articles/micronano201636
http://aip.scitation.org/doi/full/10.1063/1.4961247

Read the coverage by Barbara Moran:
www.bu.edu/research/articles/wireless-microelectromechanical-systems

In Deutsch:
www.elektronik-informationen.de/drahtlose-leistungsversorgung-fuer-mems-systeme/150/23202/338527