Satellite is an object that orbits or rotate around another object in a particular path Orbit. Our solar system is a good example.
How satellite stable in orbit?
A satellite remains in orbit because the centrifugal force caused by its rotation around earth is counterbalanced by earth gravitational pull.
The ground station, or earth station, is the terrestrial base of the system. The process of satellite communication begins at an earth station. Here, an installation is designed to transmit and receive signals from a satellite in an orbit around the earth. Earth stations send the information to satellites in the form of high powered, high frequency (GHz range) signals.
The footprint of a communications satellite is the ground area that its transponders offer coverage, and determines the satellite dish diameter required to receive each transponder signal.