Power/Performance Bits: Nov. 18

A lighter, cheaper radio wave device
Researchers at The University of Texas at Austin reported that they have achieved a milestone in modern wireless and cellular telecommunications through the creation of a radically smaller, more efficient radio wave circulator that could be used in cellphones and other wireless devices.

The researchers said the circulator has the potential to double the useful bandwidth in wireless communications by enabling full-duplex functionality. This means devices can transmit and receive signals on the same frequency band at the same time. The magnetic-free radio wave circulator makes this possible.

Since the advent of wireless technology 60 years ago, magnetic-based circulators have been in principle able to provide two-way communications on the same frequency channel, but they are not widely adopted because of the large size, weight and cost associated with using magnets and magnetic materials.

According to the team, the device is freed from a reliance on magnetic effects, has a much smaller footprint while also using less expensive and more common materials. They believe these cost and size efficiencies could lead to the integration of circulators within cellphones and other microelectronic systems, resulting in substantially faster downloads, fewer dropped calls and significantly clearer communications.

Radio wave circulator developed by researchers at the Cockrell School of Engineering. (Source: The University of Texas at Austin)

The prototype circulator is 2 centimeters in size — more than 75 times smaller than the wavelength of operation. The circulator may be further scaled down to as small as a few microns, according to the researchers. The design is based on materials widely used in integrated circuits such as gold, copper and silicon, making it easier to integrate in the circuit boards of modern communication devices.

Atoms-width electrical wire
In research that has the potential to enable the creation not only of new micro- and nanoelectronic devices but also of a new kind of solar cell, researchers at EPFL have shown that it is possible to generate a conducting channel with a width of a few atoms in the contact zone between different sheets of insulating materials.

To generate the tiny conducting channels, the team studied sheets of material a few atoms thick, sometimes only consisting of a single layer of atoms. Like graphene, these materials are composed of atoms arranged in a hexagonal structure, similar to the cells found in beehives. The difference is that while graphene is conductive and only composed of carbon atoms, the 2D materials mentioned in the study are insulating and are composed of different elements.

The conductive “wires” could potentially serve to develop more compact and powerful micro- and nanoelectronic devices. At a few atoms wide, the wire could connect the different processors of a nanochip by taking far less space than current wires, they noted.

EPFL researchers showed it is possible to create an electrical channel a few atoms wide within two-dimensional insulating materials. Their simulations open new perspectives for the production of new electronic and photovoltaic devices. (Source: EPFL)

Other applications could include the creation of a new kind of ultra-thin and flexible solar cell since, when the material patterned with channels is subjected to sunlight, electrons present in the insulating part move toward the conductive pathways. To obtain an electric current, it then suffices simply to connect the channels.