It is also known as a wireless media.
Wireless media transmit and receive electromagnetic signals without and
electrical or optical conductor. Here
transmission and reception achieved by means of an antenna. For transmission
antenna emits signal into medium and for reception antenna picks up electromagnetic
signals from the surrounding medium. The two forms of transmission:
Directional: - In this, transmitting
antenna puts out a focused electromagnetic beam. The transmitting receiving
antenna must be aligned, known as Point-to-Point Communication.
Omni-directional:
- In this the transmitted signal spreads out in all direction and be
received by many antenna inspite of direction.
According to frequency range the wireless media is
divided into three parts:-
·
Radiowave
(30MHz-1GHz): Omni directional transmission
·
Microwave
(1-40GHz): Point-to-Point Communication
·
Infrared (100GHz-1000
THz light frequencies): Local Point to Point,
Multipoint application within confined areas.
