Carbon Nanotubes Coupled For Efficient Signal Transmission

A unique method that may enable efficient transmitting of signals from nanocomponents in electronic circuits has been developed by physicists at University of Basel. The method involoves an arrangemnt with a nanocomponent connected to two electrical conductors, which uncouple the electrical signal highly efficiently.

The miniaturization of electronic components contunues to progress. Currently, components measuring just a few nanometers (the size of around ten atoms) are being produced in research labs.

More and more electronic components can now be placed in restricted spaces, boosting the performance of future electronics even further.

Research groups all around the world are striving to use carbon nanotubes for making nanoscale components. These nanotubes have special properties, offering ability to withstand strong currents, excellent heat conduction, suitability for use as conductors or semiconductors.

Lost Signal Transmission

But signal transmission between a carbon nanotube and a significantly larger electrical conductor is still a roadblock, because large portions of the electrical signal are lost due to the reflection of part of the signal.

The problem is analogous to that of light sources within a glass object. A large quantity of light is reflected by the walls, and therefore only a small proportion reaches the outside. Usage of an antireflex coating can help counter this.

A similar approach in the field of nanoelectronics is being taken by the scientists in Basel, led by Professor Christian Schönenberger.

The team has developed an antireflex device for electrical signals. Reduction of the reflection that happens during transmission from nanocomponents to larger circuits is the device’s purpose.

A unique formation of electrical conductors of a certain length, which are coupled with a carbon nanotube was created. The researchers were then able to achieve efficient uncoupling of a high-frequency signal from the nanocomponent.

Due to the large impedance diferentials, however, coupling nanostructures with significantly larger conductors proved harder. The larger the difference in impedance between two conducting structures, the larger the loss is during transmission.

Countermeasures are essential to allow signal transmission, since the difference between macroscopic conductors and the nanocomponents is so high. The antireflex device minimizes the effect, adjusts impedances, and opens the door to efficient coupling.


V. Ranjan, G. Puebla-Hellmann, M. Jung, T. Hasler, A. Nunnenkamp, M. Muoth, C. Hierold, A. Wallraff & C. Schönenberger Clean carbon nanotubes coupled to superconducting impedance-matching circuits Nature Communications (2015), doi: 10.1038/ncomms8165

Ittustration: The clever arrangement of two electrical conductors around the carbon nanotube leads to an efficient signal transmission between the carbon nanotube and a much larger conductor for electromagnetic waves. © University of Basel, Department of Physics/Swiss Nanoscience Institute

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