Page 48 - SATELLITE AND RADAR COMMUNICATION SYSTEM

Array Antennas

An antenna when individually can
radiate an amount of energy, in a

particular direction, resulting in better
transmission, how it would be if few

more elements are added it, to produce
more efficient output. It is exactly this
idea, which lead to the invention

of Array Antennas or Antenna arrays.
Array antennas are used in satellites Figure 2.13: Example of array

to form multiple beams from single antenna
aperture.

2.3 Understand types of

earth station

Earth station

Earth Station also known as the ground station is an arrangement of

various equipment on the surface or atmosphere of the earth that is used to
transmit or receive signals in the form of voice, video, or data through single

or multiple satellites. It is sometimes called the earth terminal and is a part
of the ground segment of the satellite network.
Three types of earth station are divided as follows:

Transmit only: This type of earth station is the one that is only designed to
transmit the signals towards the satellite and has no arrangement of signal

reception.
Receive only: The type of earth station that simply performs the function of

reception of signals coming from satellite and cannot transmit the signal to
the satellite in space is known as receive type earth station.

Transmit-Receive: The earth station unit that solely handles two-way
communication i.e., sends the signal to the satellite and also receives the
signal coming from the satellite is known as transmit-receive type earth

40 station.

Satellite System Elements