What is Ka-band?
Ka-band (from K-above) covers the frequency range of 26.5–40 GHz and is the dominant band for modern high-throughput satellite (HTS) broadband services. The wide available bandwidth — approximately 13.5 GHz, compared to 6 GHz for Ku-band — allows Ka-band HTS satellites to deliver hundreds of gigabits per second of total throughput through aggressive frequency reuse across narrow spot beams.
Advantages
Ka-band's shorter wavelength means that antennas of the same physical size achieve higher gain, allowing smaller terminal dishes (0.6–0.75 m vs. 1.2–1.8 m for Ku-band) and lower-cost user equipment. The wide spectrum availability enables high data rates per carrier. Ka-band is the band of choice for satellite broadband consumer services (Viasat ViaSat-3, HughesNet Jupiter, Starlink uses V-band for feeder links), maritime HTS, and aeronautical connectivity.
The rain fade challenge
At Ka-band frequencies, atmospheric water vapour and rain attenuate the signal far more than at Ku-band. A 25 mm/hour rain event can cause 10–20 dB of additional path loss at Ka-band — equivalent to losing 90–99% of signal power. System designers mitigate this through adaptive coding and modulation (ACM), which dynamically lowers throughput during rain events to maintain link availability, and through uplink power control (ULPC), which increases terminal transmit power in rain.
Q/V-band: the next frontier
Q/V-band (37.5–51.4 GHz) offers even wider bandwidth above Ka-band and is being evaluated for feeder links on the next generation of HTS and LEO satellites. ESA's ALPHASAT demonstrated Q/V-band propagation in Europe. The severe rain fade at Q/V band requires advanced diversity techniques but the available spectrum makes it attractive for gateway-to-satellite feeder links.