Ka-band refers to the radio frequency range between 26.5 and 40 GHz, which has become the workhorse frequency band for modern high-throughput satellite (HTS) broadband systems. Both Starlink and OneWeb use Ka-band for their user links, and most GEO HTS satellites (like ViaSat-3) operate in Ka-band. The higher frequency enables smaller antennas and greater bandwidth per beam compared to the older Ku-band.
Ka-band offers a good balance between bandwidth availability and atmospheric propagation characteristics. It provides significantly more capacity than Ku-band (12-18 GHz) while suffering less rain fade than V-band. Spot beam architectures in Ka-band allow frequency reuse across many beams, multiplying total system capacity and enabling broadband speeds competitive with terrestrial fiber in many use cases.