Unguided media, also known as wireless media, are channels that allow data to be sent from one location to another without the use of physical pathways. Here are three types of unguided media:
Radio waves: These are easy to generate and can penetrate through buildings. The sending and receiving antennas need not be aligned. Frequency Range: 3KHz – 1GHz. AM and FM radios and cordless phones use Radio waves for transmission. Radio waves are further categorized into Terrestrial and Satellite.
Microwaves: It is a line of sight transmission i.e. the sending and receiving antennas need to be properly aligned with each other. The distance covered by the signal is directly proportional to the height of the antenna. Frequency Range: 1GHz – 300GHz. These are majorly used for mobile phone communication and television distribution. Microwave transmission is of two types: Terrestrial Type Microwave Transmission and Satellite Type Microwave Transmission.
Infrared: Infrared waves are used for very short distance communication. They cannot penetrate through obstacles. This prevents interference between systems. Frequency Range: 300GHz – 400THz. It is used in TV remotes, wireless mouse, keyboard, printer, etc.