What would we do without television or the internet? How can one relax after a stressful day at work without the television? How can one catch up with friends and family or binge-watch that latest series on streaming services without the internet?
All of the activities mentioned above require communications satellites. These satellites make use of different radio and microwave frequencies to transmit and receive data. This article concerns the latter and why it is used for satellite communications.
To be clear, the microwave antenna isn’t the only antenna used for satellite communication.
Microwaves in Satellite Communication
Microwaves are used for their smaller wavelength, which allows antennas to point them directly at a receiving antenna. This feature makes it possible for different microwave equipment to use the same frequency but never interfere with each other.
Another reason for the use of microwaves is their high frequency, which allows them to carry huge amounts of information.
Microwave transmission is carried out with the help of microwave antennas, which are deployed in either of the following radio bands:
- C band – 4 to 8 GHz
- X band – 8 to 12 GHz
- Ku band – 12 to 18 GHz
- K band – 18 to 26.5 GHz
- Ka band – 26.5 to 40 GHz
- Q band – 33 to 50 GHz
- W band – 75 to 110 GHz
Microwaves are best suited to communicate with geostationary satellites since they have a higher frequency and small wavelength. They are not the best for communication with satellites in low orbit.
Satellites emit microwaves with wavelengths between 1 and 10 cm. The dishes that emit the wavelengths have a larger diameter. This doesn’t produce wide diffraction, therefore, emitting a narrow beam which doesn’t spread out.
Given that, it follows that both transmitting and receiving dishes need to be aligned with one another. You can find a working example of this in a neighborhood with many satellite dish subscribers. If you take a close look at each of the dishes, you’ll find that all of them are pointed in the same direction.
Satellites in geostationary orbit are useful for communications since a microwave antenna can be aimed at them without having to know their exact location. The first geostationary satellite was used to broadcast the 1964 Summer Olympics. Major broadcast television networks have also made use of geostationary satellites to distribute programming to local affiliates. Such satellites are also used by cable TV networks.
Wireless LAN protocols make use of microwaves. If you’ve ever used Bluetooth or the WiFi then you have had experience with one of the uses of microwaves. A lot of tasks of modern living can now be done over the internet, and there’s a microwave to thank for that. Without it, buying groceries, paying bills, and booking movie tickets through smartphones and laptops won’t be possible.
Microwaves are used for satellite communication, but it isn’t the only one. A microwave antenna is used for its high frequency, which allows it to carry lots of information, and its short wavelength, which makes it easier to point directly at a receiving antenna.
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