What is meant by the term "antenna polarisation"?

Antenna polarization refers specifically to the orientation of the electric field of a radio wave relative to Earth's surface. This concept is crucial in antenna design and communication effectiveness because it impacts how well an antenna can transmit and receive signals.

When a radio wave propagates, its electric field can be oriented in different directions. For example, if the electric field oscillates vertically, it is considered vertical polarization, while horizontal oscillation denotes horizontal polarization. Choosing appropriate polarization helps ensure that the transmitting and receiving antennas match, which can significantly enhance signal strength and reduce interference.

The other options, while relevant to radio operations, do not pertain to the definition of polarization: the frequency of the radio wave involves the signal's wavelength, the height of the antenna affects its range and coverage but not its polarization, and the shape of the antenna elements can influence gain and directionality but does not define the electric field's orientation.