Applications of EM Waves in Communications

Basic Principles

The electromagnetic (EM) waves have found wide applications in the field of communication, thanks to their unique properties.
Different frequencies of EM waves have different properties which make them more suitable for certain types of communication.
The range of all possible frequencies of EM waves is called the electromagnetic spectrum. It includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

Radio Waves

Radio waves have large wavelengths and hence can diffract around obstacles, making them especially useful for long-distance communication.
They are widely used in broadcasting services for both audio (radio) and visual (television) data transmission.

Microwaves

With smaller wavelengths, microwaves are able to penetrate through the Earth’s atmosphere with little attenuation, making them ideal for satellite communication and radar systems.
One key application is in mobile phone networks, where microwaves are used to transmit voice and data signals.
Microwaves are also used for point-to-point communication in air traffic control and broadcasting transmission.

Infrared Waves

Infrared waves are commonly used for short-range communication in wireless keyboards, mice, printers, and remote controls due to their relatively lower energy which limits their range.
They also play a vital role in fibre-optic communication, providing massive bandwidth capability for data transmission.

Visible Light

Visible light, though not commonly thought of in this way, is used in communication, with lamps and lasers being used to send signals in Morse code or in fibre-optic communication.
It’s also essentially the medium of cinema, photography, and many forms of visual art.

Satellite Communication

In satellite communication, EM waves with high enough energy to penetrate the Earth’s atmosphere (e.g., microwaves) are sent from a ground station to a satellite. The satellite amplifies the signal and retransmits it back to different locations on Earth.
Satellite communication makes global broadcasting and networking possible, providing services such as GPS, TV broadcasting, and internet connectivity.

Remember, understanding how various types of EM waves are applied in communication systems will equip you with a deeper understanding of how modern technology works. This can form a contextual basis for understanding more specific applications and principles within science.