As mobile technology continues to evolve, smartphones, wireless networks and connected devices are handling more signals than ever before.
Future 6G networks are expected to support even more data, faster speeds and a growing number of connected devices.
To make all of this possible, the tiny electronic components inside wireless chips must become smaller, faster and more energy efficient.
Now, researchers have developed a new type of miniature switch that could help make future wireless devices smaller while reducing their power consumption. Their findings were published in the journal Nature.
The international research team, led by Associate Professor Mario Lanza from the National University of Singapore, created tiny memory-based radio-frequency switches that can remember their settings even after power is turned off.
Inside every smartphone, mobile base station and many modern electronic devices are radio-frequency switches.
These switches act like traffic controllers for wireless signals, deciding which signals should pass through and which should be blocked.
Older 2G phones only needed about four of these switches. Today’s 5G devices require around 50, and future 6G systems may need more than 100. As more switches are added, wireless chips become larger, more expensive and use more electricity.
The newly developed switches solve part of this problem because they are incredibly small and do not need continuous power to keep their settings.
The technology is based on devices called memristive switches. Unlike traditional switches that rely on transistors or diodes, memristive switches can “remember” their last state. Once switched on or off, they stay that way until they receive another electrical signal.
To build the switches, the researchers used an ultra-thin layer of a material called hexagonal boron nitride, placed between two tiny gold electrodes. A short electrical pulse creates or removes an extremely small gold pathway through the material. This changes the switch’s electrical resistance and determines whether radio signals pass through, are weakened or are blocked.
One of the biggest advantages is size. Each switch measures just 2 by 2 micrometers, making it around 25,000 times smaller than many conventional radio-frequency switches currently used in chips. The saved space could allow engineers to add many more wireless functions without increasing chip size.
The researchers also demonstrated that these tiny switches can be integrated into existing gallium nitride (GaN) microchips without redesigning the chip’s main electronic circuitry. Instead, the new switches were added to the upper layers of commercially manufactured chips, where existing transistors controlled their operation.
The team then tested the switches inside working electronic circuits rather than as individual laboratory devices. The switches successfully adjusted signal strength, directed signals along different paths and changed the frequencies allowed through a filter.
The devices operated at frequencies up to 100 gigahertz, covering today’s 5G bands as well as frequencies being explored for future 6G communications. In testing, the best switches allowed about 93 percent of the signal power to pass through, showing performance close to existing commercial technologies.
The switches also proved stable. They kept their settings after being stored for two weeks and even after spending 24 hours at temperatures as high as 175 degrees Celsius.
Although the results are promising, the researchers say more work is needed before the technology reaches commercial products. Some of the tiny switches failed after repeated use because their extremely thin electrodes became damaged. Improving durability and simplifying manufacturing will be key steps before the technology can be mass-produced.
Even so, the study shows that these tiny memory switches could become an important building block for future wireless electronics. By reducing chip size and lowering energy use, they may help power the next generation of smartphones, mobile networks, self-driving cars and other advanced wireless technologies.
