HIGH SPECTRAL-EFFICIENCY COMMUNICATION in X BAND for SMALL EARTH OBSERVATION SATELLITES-RESULT of 505 Mbps Demonstration and PLAN for 2 Gbps LINK -

A compact 64APSK X band transmitter for small satellites with maximum 538 Mbps, mass of 1.3 kg, and power consumption of 22 W has been developed. This transmitter was onboard on Hodoyoshi 4 satellite with 66 kg mass and 505 Mbps downlink was demonstrated. The main characteristics of this downlink system are as follows: i) GaN HEMT X band power amplifier with a high power efficiency and a small nonlinear distortion, ii) application of an error correction code with high coding gain. We present a plan of 2-3 Gbps downlink system in X band.