Inter-Organizational Value Chain

MICROWAVE:- These are a form of electromagnetic radiation with wavelengths ranging from as long as one meter to as short as one millimeter, which is equal to the frequencies between 300 MHz (0.3 GHz) and 300 GHz. This definition includes both UHF and EHF both are millimeter waves, and various sources use different boundaries. In every case, microwave includes the entire SHF band (3 to 30 GHz, or 10 to 1 cm) at minimum, with RF engineering often putting the lower boundary at 1 GHz (30 cm), and the upper around 100 GHz (3 mm).The prefix "micro-" in "microwave" is not meant to suggest a wavelength in the micrometer range. It indicates that microwaves are "small" compared to waves used in typical radio broadcasting, in that they have shorter wavelengths. The boundaries between far infrared light, terahertz radiation, microwaves, and ultra-high-frequency radio waves are arbitrary and are used variously between different fields of study.                                            

Microwave technology is extensively used for point-to-point communications i.e. in non-broadcast use. These waves are especially suitable for this use since they are more easily focused into narrow beams than radio waves, allowing the reuse of frequency; their higher frequencies allow broad bandwidth and high data transmission rates, and antenna sizes are smaller than at lower frequencies because antenna size is inversely proportional to transmitted frequency. These waves are used in spacecraft communication, and much of the world's data, TV, and telephone communications are transmitted long distances by microwaves between ground stations and communications satellites. These waves are also employed in microwave ovens and in radar technology.

Uses of Microwaves:-

·        Communication:- Before the arrival of fiber-optic transmission, most long-distance telephone calls were carried via networks of microwave radio relay links run by carriers.

ü Wireless LAN protocols, such as Bluetooth and the IEEE 802.11 specifications use microwaves in the 2.4 GHz ISM band. Licensed long-range (up to about 25 km) Wireless Internet Access services have been used for almost a decade in many countries in the 3.5–4.0 GHz range.

ü Metropolitan area network (MAN) protocols, such as WiMAX (Worldwide Interoperability for Microwave Access) are based on standards such as IEEE 802.16 which are designed to operate between 2 to 11 GHz. Commercial implementations are in the 2.3 GHz, 2.5 GHz, 3.5 GHz and 5.8 GHz ranges.

ü Mobile Broadband Wireless Access (MBWA) protocols based on standards specifications such as IEEE 802.20  operate between 1.6 and 2.3 GHz to provide mobility and in-building penetration characteristics similar to mobile phones but with much greater spectral efficiency.

ü Microwaves are used in broadcasting and    telecommunication transmissions due to their short wavelength, highly directional antennas are smaller and therefore more practical than they would be at longer wavelengths (lower frequencies).

TYPES OF MICRO WAVES-

·      TERRESTERIAL MICROWAVE-

Microwave transmission is where information is transmitted via radio waves. It is used in terrestrial microwave radio broadcasting. This is when links are relayed in telecommunications networks. This can include backbone or back-haul carriers featured in cellular networks.

The terrestrial microwave transmission typically uses the radio frequency spectrum 2 to 40 GHz. The transmitter is a parabolic dish which is shaped like a bowl and is mounted as high as possible to get the best frequency and transmission. Both the private networks and common carriers can use terrestrial microwaves. An unblocked line of sight must be available between the source and the receiver. Seeing as the Earth is a curved sphere, the stations (otherwise known as repeaters) must be spaced 30 miles apart.

Terrestrial microwaves are used for both radio (voice) and television transmission. It can also be used for closed-circuit television (commonly known as CCTV) but short point-to-point connections between buildings or a data link between Local Area Connections (LANs) will be needed for the transmission to work.

There are many advantages of terrestrial microwave transmission. It can cover a wide bandwidth and has multi-channel transmissions. It can be used for both long-haul or high capacity short-haul transmissions. Also, it requires fewer amplifiers and repeaters, making it efficient and of good quality.

The disadvantages of terrestrial microwave transmission are that it can be expensive to obey to the 30-mile line of sight requirement. The frequency bands must be regulated. This means employing extra staff and can be costly seeing as there are a large number of terrestrial microwave transmitters in the world!

·    SATELLITE MICROWAVE:-

A satellite is any object that revolves around a planet in a circular or elliptical path. The moon is Earth's natural satellite at 240,000 miles distant. Other satellites that fulfill this definition are man made and have been launched into orbit to carry out specific functions. These satellites are typically between 100 and 24,000 miles away.

Satellites have many purposes including data communications, scientific applications and weather analysis.

Satellite transmission requires an unobstructed line of sight. The line of site will be between the orbiting satellite and a station on Earth. Satellite signals must travel in straight lines but do not have the limitations of ground based wireless transmission, such as the curvature of the Earth.

Microwave signals from a satellite can be transmitted to any place on Earth which means that high quality communications can be made available to remote areas of the world without requiring the massive investment in ground-based equipment.

A communications satellite is an artificial satellite sent to space for the purpose of telecommunications. Modern communications satellites uses variety of orbits including geostationary orbits.

For point-to point services, communications satellites provide a microwave radio relay technology complementary to that of communication cables. They are also used for mobile applications such as communications to ships, vehicles, planes and hand-held terminals, and for TV and radio broadcasting.