International team develops high-frequency switch for future 6G networks

Researchers from the UAB (University of Barcelona) have been involved in the development of a switch, a device essential for telecommunications, capable of operating at very high frequencies with lower power consumption than previous technologies. This technology is being applied in the new 6G mass communication systems, which are more sustainable in terms of energy consumption than current devices. The research was recently published in Nature Electronics.

An essential element for controlling signals in electronic communication devices is the switch, whose function is to pass an electrical signal (on state) or block it (off state). The fastest elements currently used to perform this function are silicon-based (so-called RF silicon-on-insulator MOSFET switches) and operate using signals with frequencies of tens of gigahertz (GHz). However, they are volatile and require a constant power source to maintain the on state.

To improve current communications systems and meet the demands for ever-increasingly faster communications speeds driven by the Internet of Things (IoT) and virtual reality, these elements need to operate at higher signal frequencies and with improved performance.

An international collaboration of researchers from the UAB School of Telecommunications and Systems Engineering has developed, for the first time, a switch that operates in a frequency range of up to 120 GHz, twice the operating frequency of current silicon-based devices, and does not require the application of a constant voltage.

The new switch uses a non-volatile material called hBN (hexagonal boron nitride) and allows the on/off state of the switch to be activated by applying a voltage pulse instead of a constant signal, thus achievable energy savings are enormous.

“Our research team from UAB’s Department of Telecommunications and Systems Engineering was involved in the design of the device and its experimental characterization in the lab,” explains researcher Jordi Verdú.

“For the first time, we have been able to demonstrate a switch based on the non-volatile material hBN operating in the frequency range up to 120 GHz. This suggests that this technology could be used in the new 6G mass communication systems, where large numbers of these elements will be needed.”

For Verdu, this is “a very important contribution towards technologies that are much more sustainable not only in terms of device performance but also in terms of energy consumption.”

These devices work by exploiting the property of memristance, where the electrical resistance of a material changes when a voltage is applied. So far, very fast switches have been experimentally developed from memristors (devices with memristance) made from two-dimensional networks of hexagonal boron nitride (hBN) bonded to form a surface.

With this arrangement, the device could reach frequencies up to 480 GHz, but only for 30 cycles, making it impractical. The new proposal uses the same materials, but arranges them layer by layer (12 to 18 layers total). This gives it a high enough stability of about 2000 cycles to operate at 260 GHz and be implemented in an electronic device.