A microwave is an electromagnetic radiation wave. Microwave wavelengths may range from a millimeter to a meter in relation to frequencies between 300 GHz and 300 MHz. Those ranges represent a broad definition of microwaves and include EHF and UHF bands. Depending on the source, microwave frequency definitions may vary in smaller, more specific ranges. Microwaves are often used in satellite communications, however, radio waves are used as well. This blog will explore why microwaves are used for satellite communications and when they are the ideal choice.
Radio Waves or Microwaves?
Both radio waves and microwaves are useful in satellite communications. They are both forms of electromagnetic radiation and radiofrequency radiation. What makes one more useful than the other? The answer lies in the distance of two communication points. The wavelengths of radio waves have less energy and are often reflected or dissipated by the ionosphere. However, the wavelengths of microwaves have more energy and pass through the ionosphere. Because of this, microwaves are better for communicating with geostationary satellites that are a long distance away, and radio waves are better for communicating with low-orbiting satellites. For example, radio waves are useful for broadcasting radio programs and television stations, and microwaves are useful for Wi-Fi, GPS devices and mobile phones.
The frequency of electromagnetic waves affects how they behave in the atmosphere. Microwaves have a higher frequency than radio waves. Geostationary satellites that microwaves communicate with are often 36,000 km above the earth. Satellites that are lower in the orbit can communicate with a lower frequency of electromagnetic waves.
To communicate with satellites, digital signals are used. Digital signals are advantageous because they do not lose energy as fast and are less affected by noise than analog signals. Microwaves that come from satellites are often between 1 cm and 10 cm. However, satellite dishes that receive the signals have a larger diameter to reduce diffraction. Exact alignment between the two points is necessary for optimal results. This is why you often see houses in rows that have satellite dishes all pointing in exactly the same direction.
Why Microwaves Are Used for Satellite Communication
So, why do companies choose to use microwaves for satellite communication? As you learned earlier, they are used when it is necessary to communicate with satellites that are higher in the orbit. Lower frequencies of waves would either be absorbed and dissipated or bounce off and return to Earth. However, there are also a few other reasons why microwaves are useful for satellite communication. These are three other reasons:
- High-gain microwave antennas can be small enough for satellite dishes.
- Microwave frequencies facilitate higher bandwidth and data transmission rates.
- Using a minimum amount of power, microwaves can be formed into strong directional beams for improved long-distance communications.
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