Polarisation is a property of electromagnetic waves used in satellite communications, defining the orientation of the electric field component of the wave. The orientation of this electric field is essential for efficient signal transmission and reception, ensuring reliable and high-quality communication between satellites and ground stations.

In satellite communication systems, electromagnetic waves are commonly transmitted and received in either linear or circular polarisation. Linear polarisation involves aligning the electric field of the wave in a specific direction, such as horizontal or vertical. Circular polarisation, on the other hand, rotates the electric field of the wave in a circular motion, either clockwise or counterclockwise.

The choice of polarisation depends on various factors, including the type of communication system, the specific application, and the propagation characteristics of the signal. Linear polarisation is commonly used in many satellite communication applications because it is relatively simple to implement and provides efficient signal propagation over long distances. It is widely used in broadcasting, telecommunications, and data transmission.