Antenna Used In Satellite
Antenna receive the uplinke signal and transmit to downlink signal . In addition they provide single link for the satellite telemetry, command and ranging system which in conjunction with attitude control subsystem provides beacon tracking single for precise pointing of the antenna towards the Earth coverage areas .The design of satellite antenna is conditioned by the required coverage. It should be remembered that antenna are the one of the key element in a satellite communication system since their gain value directly determine the amount of received power.
Types of antenna system use in satellite communication
Parabolic Antenna
 |
Parabolic Antenna |
A parabolic antenna is a high- gain reflector antenna used for radio, television and data communication, and also for radio-location (RADAR ), on the UHF and SHF part of the electromagnetic spectrum. the restively short wavelength of electromagnetic(radio ) energy at these frequencies allows reflectors to exhibit the very desirable highly directional response for both receiving and transmitting. A typical parabolic antenna consists of a parabolic reflector illumined by a small feed antenna. the reflector is a metallic surface formed into a paraboloid of revolution and (usually ) truncated in a circular rim that forms `the diameter of the antenna. This paraboloid possesses a distinct focal point by virtue of having the reflection property of parabolas in that a point light source at this focus produces a parallel light beam aligned with the axis of revolution. The feed antenna is placed at the reflector focus. This antenna is typically a low -gin type such as a half-wave dipole or a small wave guide horn. in more complex designs, such as the cassegrain antenna , a sub-reflector is used to direct the energy into the parabolic reflector from a feed antenna located away from the primary focal point. The feed antenna is connected to the associated radio- frequency (RF) transmitting or receiving equipment by means of a coaxial cable.
0 comments:
If you have any doubts,please let me know