Mini-antennas could power brain-computer interfaces, medical devices
The new mini-antennas play off the difference between electromagnetic (EM) waves, such as light and radio waves, and acoustic waves, such as sound and inaudible vibrations. ...at any given frequency, an EM wave has a much longer wavelength than an acoustic wave.
The trick is, of course, to quickly turn the incoming EM waves into acoustic waves. To do that, the two-part antenna employs a thin sheet of a so-called piezomagnetic material, which expands and contracts when exposed to a magnetic field. If it's the right size and shape, the sheet efficiently converts the incoming EM wave to acoustic vibrations.
The team created two kinds of acoustic antennas. One has a circular membrane, which works for frequencies in the gigahertz range, including those for WiFi. The other has a rectangular membrane, suitable for megahertz frequencies used for TV and radio. Each is less than a millimeter across, and both can be manufactured together on a single chip. When researchers tested one of the antennas in a specially insulated room, they found that compared to a conventional ring antenna of the same size, it sent and received 2.5 gigahertz signals about 100,000 times more efficiently, they report today in Nature Communications.
Tiny antennas could reduce the size of cellphones, shrink satellites, connect tiny objects to the so-called internet of things, or be swallowed or implanted for medical monitoring or personal identification. ... With a neurosurgeon at Massachusetts General Hospital, he’s also creating brain implants for reading or controlling neural activity—helpful for diagnosing and treating people with epilepsy, or eventually for building those sci-fi brain-computer interfaces.
See the full story here: http://www.sciencemag.org/news/2017/08/mini-antennas-could-power-brain-computer-interfaces-medical-devices