This paper describes the system concept of a millimeterwave personal s
atellite communication, which includes the configuration of the commun
ication system, the satellite system, and the earth terminal system. T
he system has a large channel capacity and achieves high performance t
hrough a flexible channel set-up method, efficient frequency reuse, an
d onboard communication equipment such as a baseband channel switching
processor and a modulator and demodulator (Modem). Two examples of co
mmunication systems are shown, in which the information bit rate, the
number of multi-beams, and the antenna diameters are different. On the
assumption that a 2 ton class satellite will be used, rough estimates
are made of the size, weight, and power consumption of the onboard co
mmunication system and bus system of the satellite. In addition, detai
ls are given regarding the specifications and performance of trial pro
ductions of communication equipment such as the switching processor, t
he Modem, the TWTA, and the LNA. Finally, the key technical issues for
establishing a millimeterwave personal satellite communication system
are also discussed.