Geosynchronous synthetic aperture radar satellites(GEO SAR)orbiting at an altitude around 36000 km were firstly proposed in 1980s with an orbit inclination of 50 degrees to cover North and South America.Though the ultra-high orbit has overwhelming advantages of 1-day revisiting time and wide coverage,the strong requirements on antenna sizes and power budgets were difficult to satisfy with the contemporary Geosynchronous synthetic aperture radar satellites (GEO SAR) orbiting at 36000 km were initially proposed in 1980s with an orbit inclination of 50 degrees to cover North and South America. How the ultra-high orbit has overwhelming advantages of 1-day revisiting time and wide coverage, the strong requirements on antenna sizes and power budgets were difficult to satisfy with the contemporary