A research team southwestern China says they have built a powerful microwave device with ultra-high output in a frequency increasingly used by business and the military. The researchers in Mianyang, Sichuan province, said the device could generate a short pulse in the Ka microwave band reaching 5 megawatts in power, two orders of magnitude higher than other publicly known results. They said the technology would not only find applications in satellite communications, but also radar, nuclear fusion and medical research. “There is an enormous interest in high-power microwave sources in the Ka band,” said Li Shifeng, a lead scientist for the research project with the China Academy of Engineering Physics in a paper published in domestic peer-reviewed journal High Power Laser and Particle Beams on Wednesday. The Ka (K above) band is a high-frequency section of the microwave spectrum between 26.5 and 40 gigahertz. SpaceX’s Starlink satellites , for instance, use part of the Ka band to communicate with ground stations. The US Army also plans to upgrade its newest combat drones to use the Ka band by 2027. If at high enough power levels, a microwave radiation source operating in or near the frequency range can jam communications or even damage some sensitive hardware of devices using the band. For years, the most powerful devices in the Ka band have been limited to just a few megawatts. Increasing the power often led to a sharp decline in efficiency and stability, according to Li and colleagues. The Sichuan team’s device fires high-energy electrons through a tube and converts the electrons to high-power microwaves with a cone-shaped muzzle. The design, known as a relativistic klystron amplifier (RKA), was proposed by US naval researchers in the late 1980s. Previous prototypes built with the design had only achieved a few hundred kilowatts of power output in the Ka band. Li’s team said they rearranged the layout of some critical components so that each physical process used in the equipment could be measured and fine-tuned independently. The new prototype generated a 501 megawatt output in an experiment. Computer modelling suggested that there is still room for improvement, according to their paper. A Beijing-based space scientist developing high-speed communication technology for satellites said the device had potential to become a high-power microwave weapon. The microwaves generated by the machine could be 100 million times more powerful than those used by most communication devices. “This is overwhelming just to think about,” said the researcher who spoke on condition of anonymity because he was not authorised to speak to the media. A physicist studying high-power microwave technology in the United States said the Chinese prototype was unlikely to threaten Starlink satellites for now. “The distance from a ground-based system to the satellites is huge, so this would not be effective,” said the researcher who had been following the research by Li’s team but asked not to be named due to the sensitivity of the technology. A recent study by Chinese satellite engineers said a ground station would need more than a gigawatt of power to effectively jam or damage new satellites protected by new technology. China needs Nasa, SpaceX hotline to avoid space collisions, scholar says SpaceX chief executive Elon Musk said earlier this month that the Starlink service over Ukraine had been jammed for several hours at a time. Starlink sent a large number of user terminals to Ukraine after Russia’s invasion. These terminals communicated with the satellite using a lower frequency in the Ku band. Musk said the jamming was bypassed with a software upgrade. “Am curious to see what’s next,” he said in a tweet on March 5. SpaceX did not immediately respond to a request for comment.
