Proposed integrated-circuit modules called "nanoconverters" would derive DC power from impinging electromagnetic beams having frequencies in the terahertz range. Nanoconverters are composed of microscopic antennas and diodes (see Figure 1) resembling rectennas that have been developed to perform the same function at frequencies in the gigahertz range. The submillimeter wavelength nanoconverters would make it possible to incorporate the antenna elements and diodes on structures much smaller than those of prior rectennas, thereby opening up opportunities for noncontact transmission of power to a variety of microelectronic devices, including surgically implanted medical devices and untethered microscopic robots.

An Antenna-and-Diode Combination (a rectenna) would convert power from an impinging terahertz radio beam to DC. The transmission line and RF filter confine the terahertz signal to the diode and allow DC to be removed.

The basic concept of radio beaming of electric power through space without the use of wires was explored before World War II and has been used at microwave frequencies. Novel aspects of the terahertz nanoconverter include:

  1. Fully integrated monolithic rectennas at submillimeter dimensions,
  2. Direct integration auto microrobots and devices,
  3. Fairly high radio frequency (RF) to DC conversion efficiency with focusing optics,
  4. Greater penetration in biomaterials and many plastics than infrared (IR) or visible wavelengths,
  5. Negligible tissue damage due to nonresonant frequencies and low beam density, and
  6. Fully integrated packages for direct RF in DC out.

Techniques, processes, and equipment needed for manufacturing circuitry with dimensions comparable to those of nanoconverters have already been developed for manufacturing GaAs-based sensors and sources at the frequencies. The nanoconverters could be used to remotely transmit power to microdevices in hostile environments or through smoke and dust.

This work was done by Peter Siegel of Caltech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at under the Computers/Electronics category.