Satellite frequency bands: What are they used for?

In the early “wild west” days of wireless communications, there were no established frequency bands, nor any widespread recognition of the need for them. But that perception changed abruptly with the 1912 sinking of the RMS Titanic. More than 1,500 people died because the ship was unable to pick up urgent warnings about icy conditions. Why were these critical advisories missed? Partly because the ship relied on channels that were open to everyone, without restrictions. And partly because the ship’s Marconi wireless telegraph machine was busy transmitting passenger messages to family and friends ashore, rather than monitoring for emergency alerts.

Shortly after, the first laws to regulate radio communications were introduced. It had become glaringly apparent that the radiofrequency spectrum needed to be divided into different bands for different uses – so that communication could flow unimpeded. Radio technology has of course evolved since the telegraph, and today, satellite communication relies on the efficient use of RF spectrum to transmit data between Earth and satellites in orbit.

What is radio frequency?

The frequency of an RF signal describes the rate at which the underlying electromagnetic wave oscillates as it propagates through space. It is measured in Hertz, where 1 Hz represents one oscillation per second. RF signals can have frequencies ranging from a few kilohertz (kHz) to several hundred gigahertz (GHz).

 Satellite communications and the RF spectrum

Satellite networks typically use a frequency range between 1 GHz and 40 GHz. This range is further subdivided into lettered bands for easy reference: L, S, C, X, Ku, K and Ka.

Note that satellite frequency allocation and band usage is not standardized on a global scale. Three different organizations have established their own naming conventions and band ranges: the International Telecommunication Union (ITU) under the United Nations, a NATO-aligned collective, and the Institute of Electrical and Electronics Engineers (IEEE). At Orbital Research, we use the IEEE band labels most often – which is what is represented above.

Choosing the right slice of satellite spectrum

Each band has advantages and disadvantages in terms of data rate, signal strength, and susceptibility to interference. The choice of band is determined by many different factors, including regulatory requirements and the specific application. Below are some of the key considerations:

• Propagation characteristics. How different bands propagate through the atmosphere, considering factors like atmospheric attenuation and rain fade.
• Interference. Mitigating interference from other satellite systems, terrestrial networks, and sources of electromagnetic interference.
• Available spectrum. Assessing the availability of spectrum allocated for satellite communications services, considering congestion and availability for specific applications.
• Data rate requirements. Selecting a frequency band that can support required data rates and bandwidth, taking modulation and coding schemes into account.
• Environmental considerations. Weather conditions, geographic location and terrain can affect satellite link performance.

How is each satellite frequency band used?

Satellite technology is advancing at a rapid clip, paving the way for more and more applications. Some frequency bands are used for specific applications, and some are more versatile. Multiple bands can be used for the same application – but generally speaking, higher frequency bands permit faster data transfer.

 L band frequency (1-2 GHz)

• Versatile frequency range used for mobile satellite services (MSS) such as sat phones, global navigation satellite systems (GNSS) such as GPS, and satellite radio such as SiriusXM
• Communication for aeronautical and maritime applications – including aircraft-to-satellite communication for air traffic control, flight and vessel tracking, and ship-to-shore communication
• Popular for Internet of Things (IoT) connectivity due to its ability to penetrate obstacles, enabling remote monitoring and control of assets in industries such as agriculture, energy, and transportation

 S band frequency (2-4 GHz)

• Widely used for weather radar and meteorological observations including precipitation detection, storm tracking, and atmospheric monitoring due to its ability to penetrate clouds and heavy rain
• Supports radio astronomy and the study of celestial objects and phenomena – including pulsars, galaxies, and interstellar gas clouds
• Offers reliable voice and data communication over large geographic areas, making it valuable for applications such as emergency communication, remote connectivity, and maritime safety
• Effective for satellite tracking and telemetry applications, allowing operators to monitor and control satellites in orbit
• Employed in remote sensing and Earth observation (EO) satellites for collecting data on a wide range of environmental parameters, such as soil moisture, vegetation health, and ocean surface conditions 

 C band frequency (4-8 GHz)

• Trusted spectrum for telecommunications services, including long distance voice and data communication over both terrestrial and satellite-based networks
• Used for satellite television broadcasting, enabling the delivery of a wide range of channels to viewers worldwide
• Preferred range for weather radar and Earth observation due to its moderate frequency, which can penetrate clouds and atmospheric interference with greater accuracy
• Employed in teleports and Very Small Aperture Terminal (VSAT) systems to provide reliable connectivity in remote and rural areas where terrestrial infrastructure is limited
• Supports satellite news gathering (SNG) systems for transmitting live video and audio feeds from remote locations to broadcasting studios in real time

 X band frequency (8-12 GHz)

• Specialized frequency band for military communication applications – such as command and control, intelligence gathering, and tactical communication – due to its ability to provide secure and reliable communication links, high data rates, and robustness against interference 
• Employed for high-resolution radar imaging applications, including surveillance, reconnaissance, and target tracking
• Reliable satellite-based voice, data, and video communication services for defense agencies, government organizations, and emergency responders – ensuring connectivity in critical situations
• Utilized in scientific research applications such as radio telescopes and space exploration to provide insights with high sensitivity and resolution

Ku band frequency (12-18 GHz)

• Extensively used for providing direct-to-home (DTH) satellite television broadcasting services with high-quality audio and video transmission
• Ideal for VSAT communication, fixed satellite services (FSS), and video distribution – offering high data rates and efficient bandwidth utilization
• Employed for broadband internet access services, particularly in remote and rural areas where terrestrial infrastructure is limited
• High frequency Ku band antennas are used onboard ships, airplanes, and oil rigs to establish satellite links for crew communication, safety services, and operational data exchange

 K band frequency (18-26.5 GHz)

• Versatile frequency band used for satellite communication, radar systems and microwave links
• Ideal for radio astronomy and remote sensing applications, supporting detailed observation and analysis of celestial objects 
• Serves diverse market segments with high frequency, ample bandwidth, and advanced capabilities

Ka band frequency (26.5-40 GHz)

• Cutting-edge spectrum supporting high speed broadband internet access, in-flight WiFi, and advanced satellite TV services including ultra-high-definition (UHD) signals
• Enhanced resolution and accuracy for radar imaging and military communication – offering high data rates, low latency, and anti-jamming capabilities
• Enhanced Earth observation including incredible, high-resolution imagery and precise measurements of the Earth surface for various applications – including agriculture, forestry, urban planning, disaster management, and damage assessments

Because of the exponential increase in the use of satellites, congestion has become a major issue in the lower frequency bands and higher bands – even beyond Ka – are becoming more and more popular. These bands provide access to wider bandwidths but are also more prone to signal degradation due to rain fade (the absorption of radio signals due to atmospheric moisture), so new technologies are being developed to ensure they can be used efficiently.

Q band frequency (36-46 GHz)

The Q band is not officially recognized by ITU or IEEE, however it is recognized by the Infrared Space Observatory (ISO). Although not yet widely used, Q band offers potential advantages for specialized applications that require high data rates, precise communication, or advanced sensing capabilities. As the technology advances and demand for high-capacity communication increases, the Q band will likely see expanded use.

V band frequency (40-75 GHz)With increasing congestion in the high throughput satellite frequency bands, particularly with constellations like Starlink relying on the Ku/Ka bands, the V band is emerging as a promising alternative. Much of its capacity is unlicensed or lightly licensed, providing tempting fruit for early adopters. The V band can support even larger bandwidth than the Ka band – and with even smaller antennas.

 

In summary

Each satellite frequency band serves a purpose based on its unique characteristics – from providing global internet connectivity to monitoring the Earth’s environment.

 The L band facilitates mobile satellite services and navigation systems, while the C band is entrusted with telecommunications and weather radar. Ku band satellites are crucial for direct broadcast satellite services and broadband internet access, while Ka band systems are known for high-speed connectivity and advanced radar imaging capabilities. X and K band frequencies are essential for military communication, radio imaging, and radio astronomy – providing secure and precise data transmission. While the Q and V bands are less commonly used, they offer potential advantages for applications requiring high data rates, precise communication or advanced sensing.

 As the technology continues to evolve, satellite frequency bands will remain essential for meeting growing demands for global connectivity, communication, and observation – and to ensure a communication breakdown as experienced by the crew of the Titanic, never happens again.