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Ð Highly directional antennas are used for line-of-sight propagation routes. Transmission frequencies are in the range
                 4 to 12 GHz. Depending on their distance, the antennas’ diameters can range from 12 inches to several feet and are
                 typically parabolic.
                                                                       Signals


                          Microwave
                           antenna








                                                                 Terrestrial Microwave


              Ð ÐSatellite  Type  Microwave  Transmission:  The  electronic  wave  used  in  satellite-type  microwave  transmission  is
                 electromagnetic in nature and is transmitted by a source. The source contains transmitting antennae, which amplify
                 the source wave—a signal—and rebroadcast it to the recipient antennae. One of the finest satellite type microwave
                 transmission applications is the Global Positioning System (GPS).
                                                                  Satellite








                                                   UP link                   Down link












                                         First Earth Station                 Second  Earth Station

              Infrared

              Infrared transmission is used for short-range communication. Between 300 GHz and 400 THz is the infrared spectrum’s
              frequency region. It is employed for close-quarters contact, such as data transfer between two cell phones, TV remote
              control operation, and data transfer between a computer and a cell phone. The data rate will be very high because
              it allows a large amount of bandwidth. The walls block the passage of infrared radiation. Thus, the adjacent rooms
              cannot interfere with infrared communication taking place in one room.















                               Television                       Infrared Radiations                Remote

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