Collin Arocho
22 October

RF energy systems have undergone a huge transformation since the early days of the tube-based magnetrons. But according to High Tech Institute trainer Klaus Werner, while the crude power of the tube is tough to match, the new generation of solid-state RF integrated circuits offers unprecedented control, efficiency and reproducibility.

Klaus Werner didn’t get a usual start in the field of RF energy solutions. After studying physics at the University of Aachen, he came to Delft University of Technology to further develop CVD systems for semiconductor technology. “At the time, I was just meant to be there for six months,” remembers Werner. But eight years and a PhD in silicon germanium growth in CVD-type systems later, Werner found himself still in Delft. “It was definitely time for a new challenge,” he recalls. Then, in 1995, Werner joined the MOS-3 fab in Nijmegen for 10 years before going to Eindhoven to the Philips team responsible for laser displacement sensors – those that are still used in computer mice today.

The fit wasn’t quite right for Werner, and the 3+ hours of commuting every day for work simply wasn’t working. So back to Nijmegen he went, becoming part of the RF power group at NXP. “The group was mostly concerned with the development of semiconductor technology and devices for high-power, high-frequency applications of RF. Most notably, in the areas of base stations for the cellular network, telephone, radar systems, and to a large extent, radio-TV transmission,” Werner describes. But it was while he was there at NXP that he saw people were applying the electromagnetic waves not for communications and data but using their sheer energy to power plasmas for lasers, lights and even medical applications, for example in hypothermia.

White goods

Suddenly, activity in the solid-state RF energy realm really started to heat up, specifically driven by white-goods companies, which got their name from the standard of white-coated exteriors of home appliances. “Whirlpool and several others saw a business opportunity to improve microwave ovens in the way they heat food,” explains Werner. “That’s when we started the RF Energy Alliance, an industry consortium that set out to establish standards, create roadmaps and develop new generations of the technology to build consensus and bring down cost.” But a few years in, and the white-goods companies pulled out, as it was simply taking too long for them to bring down costs to have a competitive offer against the magnetron-powered ovens.

“NXP, as a semiconductor company, wanted to focus on components and the technology behind the components. At the same time, I was focused on pushing forward with openly spreading the knowledge and interest of the technology and its applications, and in the end, we decided to split,” says Werner. “That’s when I decided to jump into the gap that I saw in the RF-energy field, and created Pink RF – taking on the name ‘pink’ as a nod to the breast cancer support organization Pink Ribbon – with an overall desire to develop the technology for wide use in areas that could really help people’s lives, for example in medicine.”

Sharing knowledge

Despite the RF Energy Alliance folding, Werner was a firm believer in the promise of the technology and knew there was real value in the efforts of the failed consortium. “One of the major hurdles in getting this technology known and used by broader audiences is sharing the knowledge about it,” asserts Werner. “I was writing articles, preparing workshops and trainings, anything to increase the knowledge. I found that many people just didn’t have a solid idea of how to approach this unusual heat source.” Refusing to give up, Werner came across the International Microwave Power Institute (IMPI), which was doing a lot of the same outreach and promotional work on microwave power that he was looking for in the old RF Energy Alliance. Today, he serves as the chairman of IMPI’s RF energy section and is responsible for diffusing information around the unique technology and creating training opportunities to share his knowledge.

“That’s one of the reasons I wanted to join High Tech Institute. It’s a real institution that goes beyond simply giving workshops. It allows us to better reach technical people and connect with a specific audience and cater to its specific needs,” Werner says enthusiastically. “One of the best parts is that many participants already have a good understanding of what the technology entails. Everything they’ve already learned in school, about the behavior of waves and diffraction and refraction, still absolutely holds true. That idea alone has major implications, from a foundational aspect. It helps loosen the minds and starts to build perspective around this technology.”

New training

Werner’s first edition of the new “Solid-state generated RF and applications” training is aimed to do just that. The three-day course will give participants an inside view into the developments of the technology, from the previous generation of high-frequency tube-based magnetrons to the modern-day solid-state electronics-based energy source. “In terms of crude power, the magnetrons are tough to beat. The problem, however, stems from the lack of optimization and control of the tube and the degradation of the signal over time,” illustrates Werner. “The new generation of solid-state RF is really being driven by cellular communications, where there’s a need for high power linearity that’s created by transistors and semiconductors. This method creates a stable, efficient and, more importantly, controllable and reproducible signal that could never be realized by the magnetron.”

“There are many factors that come into play when determining how best to utilize RF energy and we’ll cover a lot of them in the new training. We’ll use a mixture of theory and practice to dig deeper into the technology. From safety aspects like radiation exposure – which is not a thing – to frequencies, behavior and interaction with matter,” describes Werner. “The reality is that this technology is extremely useful and completely scalable. From heating minute amounts of liquids under very well-controlled circumstances for Covid testing, up to cooking 1,000 liters of soup every hour. This modular technology is applicable from microjoules up to megajoules, with nearly unending possibilities.”