Beyond Ka-Band: What ESA Industry Space Days 2026 Revealed About the Future of Satellite RF

    ESA’s Industry Space Days (ISD) returned to ESTEC in Noordwijk this September for its largest edition yet: around 240 exhibitors, over 3,000 participants representing roughly 1,500 companies, and more than 10,000 pre-arranged one-to-one meetings across two days. It is one of the clearest snapshots available of where European space technology is actually headed, not where roadmaps say it’s headed. A few themes stood out. Ka-band is still the workhorse, but the industry is moving up the spectrum Walking the exhibition floor, the majority of RF hardware on display still operates below 30 GHz. That’s not a surprise: Ku- and Ka-band remain the commercial workhorses for satellite communications, Earth observation downlinks and TT&C. But “mostly below 30 GHz” is a snapshot of where deployed systems are today, not where the engineering effort is going. The bigger story in satcom right now is the migration up the spectrum. Ka-band capacity is increasingly congested, and operators are pushing feeder links into Q-band (37.5 to 42.5 GHz) and V-band (47.5 to 50.2 GHz), a combined allocation that offers roughly three times the contiguous bandwidth of Ka-band alone. ESA’s ARTES program has been actively funding Q/V-band technology development for exactly this reason, and major operators have already committed to Q/V-band feeder link architectures for their next-generation high-throughput satellite systems. Higher still, W-band (75 to 110 GHz) is being explored specifically for inter-satellite links, where the signal never has to pass through the atmosphere and so is not penalised by rain fade in the way a ground link would be.   Ground segment, not launch, is where the RF challenge lives A recurring impression from the show floor was that the “hard” RF problems on display were overwhelmingly on the ground and payload side, feeder links, antenna systems, up/down conversion, rather than in exotic new satellite platforms. There was no equivalent of a mega-constellation operator exhibiting; instead, the exhibition was dense with smaller companies building the K/Ka-band antennas, filters, converters and test equipment that every constellation, GEO payload and ground station ultimately depends on. That is a useful reminder that “space” as an industry leans more towards a ground-based and component-level business, even though the public conversation focuses on launches and satellites. Direct-to-device is pulling satellite RF into the terrestrial mobile world Interest in linking satellites directly to standard mobile devices was a visible thread across the exhibition, and it tracks a much larger industry shift. 3GPP’s Non-Terrestrial Network (NTN) standards have matured quickly: Release 18 added support for frequency bands above 10 GHz and laid the technical groundwork for direct-to-handset service in bands originally allocated to terrestrial mobile operators, and Release 19 is extending that further with regenerative payload architectures and store-and-forward IoT connectivity. Analysts now put the 5G NTN market at low double-digit billions of dollars in 2026, growing at over 30% a year, driven almost entirely by direct-to-device connectivity. For RF hardware, this means satellite payloads increasingly need to interoperate with terrestrial 5G/6G frequency plans, which is pushing new requirements into up/down conversion and RF terminal design that didn’t exist a few years ago.   Antenna design and test methods are evolving alongside the frequency shift Antenna work, particularly in K- and Ka-band, was one of the most common specialisations on show, reflecting how much of the industry’s near-term growth is still concentrated in that range. At the same time, newer antenna test approaches are emerging that move away from traditional anechoic-chamber field probing toward faster, more direct field-capture methods. As these techniques push for greater dynamic range, they place new demands on the RF power sources used to illuminate the antenna under test, a small but telling example of how progress in one part of the chain (test methodology) creates new downstream requirements elsewhere (higher-power sources at higher frequencies). Where this leaves the industry Taken together, the picture from ISD 2026 is of an industry in the middle of a spectrum migration, not at the start or end of one. Ka-band remains the commercial backbone, Q/V-band is where the funded, near-term engineering effort is concentrated, and W-band and above are being actively evaluated for inter-satellite links and specialised applications. Layered on top of that is a genuinely new demand driver, direct-to-device connectivity, that is pulling satellite RF design into closer alignment with terrestrial mobile standards than at any point in the last decade. For component and subsystem suppliers across the value chain, that combination (higher frequencies, tighter integration with terrestrial networks, and evolving test requirements) is likely to define where the next wave of European space RF investment goes.