The term wireless technology is generally associated with mobile IT equipment like cellular telephones and laptops. It is a method of data transmission, which similar to wired technology. For both these technologies the range of transmission is the prime concern. 
The three broad categories of wireless media are:
Radio - The frequency ranges from 3Hz to 300GHz. It is broken into many bands including AM (300-3000 KHz), FM (30–300 MHz), and microwave bands (3-30GHz).
Microwave - These frequencies can further be classified into Terrestrial and Satellite. The frequency usually falls in the range of 4-6GHz or 21-23GHz and the speed is usually between 1-10Mbps. In order to link networks over long distances, microwaves are used. However, two-microwave towers should have a line of sight between them. These signals are usually encrypted for the sake of privacy. The transmission frequencies of Satellite are generally between 11-14GHz with a transmission speed in 1-10Mbps ranges.
Infrared - This is just below the visible range of light ranging between 100Ghz and 1000Thz. In order to transmit the signal, a laser or light emitting diode (LED) is used. Light may interfere with the signal but infrared signals cannot travel through objects.
Wireless networks allow connecting computers without the need of wires or cables. In a wireless network the data may be transmitted over several different types of transmission medium such as microwave, radio, infrared light, or lasers.
The main disadvantages of wireless networking are that data transmission rates are not as high as those attainable through wired networks. Also security is a concern in the wireless medium.
