Satellites are regularly launched into Earth orbit to provide TV signals, communications services, geographic location services or to scan the planet for geological data. Some are sent to investigate neighboring planets, which just like those on timeless missions into remote corners of our solar system send data about their discoveries back to Earth. Modern satellites include microwave communications equipment for mission control and to communicate data. The use of Microwave frequencies enables high gain antennas to beam the signal back to base where even more powerful ground based antennas reject cosmic noise and background noise generated by the Earth itself.
Gallium Arsenide (GaAs), a III-V compound semiconductor with high electron mobility and saturated electron velocity, is well recognized for its performance advantages at microwave frequencies both in space and in Earth bound applications. In fact, GaAs can be found in many applications including your cellular phone, the base station which connects your phone call, your WiFi link and even fiber optic links.