The Drive for Innovation

On the cusp of 6G, are we also on the verge of a materials breakthrough?

The world has barely experienced a fraction of the services 5G mobile promised to deliver, and already the drive toward 6G is gathering momentum. The standardization process begins this year, and the final specifications are expected to be released in 2028, with rollout beginning in 2030. It’s proof, if more were needed, that we are an impatient and ambitious species.

Ericsson has helpfully described the 6G standardization process, which is expected to permit a much cleaner transition than we have seen in the move from 4G to 5G. Although 6G will leverage some 5G infrastructure, particularly in the core, connectivity will be standalone from the start and should perform better as a result. It’s hard to grasp, but 6G data rates and latency are expected to be about 1000 times faster than those of 5G.

The bigger picture is working toward a pervasively connected world that supports our lives and adapts to our needs, wherever we are and however those needs change in real-time. Wireless is the only connectivity that can do this for us. Realizing the necessary connections is extremely challenging at every level, from the standards-setting efforts undertaken by the 3GPP, the global body managing mobile standards, to the subcomponent level – including the new materials we must develop to build the systems that can realize the performance promised in the specifications.

As so many of the instruments and devices we connect have become highly digitized and software-defined, it can be easy to forget that the natural world around us is analog and always will be. Our digital systems must interact with this physical world, and this has fascinating implications for the antennas that will make this border traversable.

6G will take our perception of the multiple-input multiple-output (MIMO) antenna array to new levels, in pursuit of the data speeds and response times we are expecting. Configuring and tuning these large arrays will have a critical impact on efficiency and power consumption, while circuit size and system reliability will be key concerns. Switched capacitor arrays are a tried and tested solution to antenna tuning issues, but their bulk makes them unsuitable, whether in infrastructure equipment or mobile devices. These capacitor arrays also need a separate controller chip, which adds to the overall size of the system.

A clever reimagining of the switched-capacitor concept now proposes digitally tunable capacitors, realized with on-chip MEMS structures. This MEMS-within-CMOS technology also enhances reliability compared to traditional solid-state switches. The technology permits combination chips that integrate these MEMS structures with multiple sensors or switches on a single die, delivering a further boost to miniaturization, cost-efficiency and performance. This is shown to be even more impressive when you learn that the scale of these structures is about one-tenth that of conventional MEMS devices.

These are exciting developments at the component and material levels, driven by the necessity to create the real, tangible hardware we need to provide the foundation for tomorrow’s virtual and mixed-reality worlds. We can also consider some of the latest adhesive systems from the PCB industry, such as resin-coated copper (RCC) and resin-coated film (RCF), and their likely impact in this emerging world.

One application for RCC/RCF is in the construction of tiny anti-shake inductors. Manufactured at micron-scale, these devices leverage RCC or RCF’s properties to maintain their mechanical stability and ensure consistent resonance parameters when used in conjunction with miniature antenna systems. Working with materials like these to produce complex components in highly miniaturized form factors, at scale, will likely drive the development of new expertise in disciplines like microfluidics to dispense minuscule and tightly controlled volumes of adhesive.

Working at the cutting edge of materials technologies for high-performing PCBs, I’m intrigued at the change in mindset that’s happening in this field. Generally we tend to view reliability and longevity as virtues, and place value on building things that last. But this is now changing, driven by today’s emphasis on sustainability and our concerns about the long-term impact our creations are having on the environment.

A U-turn is happening, shown in developments like the biodegradable materials I mentioned last month. Made from natural fibers, instead of conventional glass fiber, this material is easy to recycle and eliminates chemicals that are hazardous to the environment. The boards break down in boiling water, permitting fibers to be reclaimed and reused, and enabling components to be easily extracted. In contrast, very little from a conventional electronic assembly based on a PCB can be salvaged or repurposed.

Long-term reliability and resilience will always be a requirement in some applications, but plenty of application areas are either single use or have low life expectancy where a biodegradable PCB would make sense. We should all admire the ingenuity that devised this new substrate class and draw inspiration as we consider the way forward for our industry and the world.

If we can imagine it, we should have faith in our ability to build it.

Alun Morgan is technology ambassador at Ventec International Group (venteclaminates.com); alun.morgan@ventec-europe.com. His column runs monthly.