300 Mbps Downlink Communications from 50kg Class Small Satellites

Recently small satellites start playing important roles in earth observation missions. It, however, is true that small satellites have drawbacks of sensor resolutions and down link data rate. As a solution to the latter drawback, we have developed novel communications system for 320Mbps down link with 16QAM for small satellites with 50kg class. We developed a new GaN HEMT X-band amplifier with high efficiency and small distortion, digital filter and pre-distortion processing with relatively low clock frequency in FPGAs, and small X-band on-board antennas. As ground segments, we are developing a compact S/X dual band ground antenna station and a high performance demodulator with turbo equalizer/decoder based on CCSDS high rate telemetry standard. These technologies will be demonstrated in 2014 by Japanese Hodoyoshi-4 satellite with 50 kg mass