Military Satellite Terminals RF Technology Trends and Outlook
Software defined radio architecture, radio-satellite-network integration as well as enabling un-interrupted and secured communications operations down to the tactical edge in a congested and contested spectrum environment will drive spending on military communications systems. Strategy Analytics forecasts spending on global military communications systems and services will grow to over $36.7 billion in 2026, representing a CAGR of 3.5%. Spending on global communications systems and services comprises radio, satellite communications (SATCOM), datalink, network and other communications systems. Satellite communications (SATCOM) systems (incorporating satellite payloads and satellite terminals) will account for 37.2% in 2026 representing the largest market opportunity in terms of military communications systems, and will be worth $13.7 billion. What are the implications for enabling RF power technologies? Which companies are positioned to benefit?
Military communications networks provide for the exchange of voice, video and data between geographically dispersed elements of a battle force. Trends driving spending on the military communications sector will be underpinned by software defined radio, satellite connectivity and network-centric IP-based communications.
Satellite communications networks consist of user terminals, satellites and a ground network that provides control and interface functions. The benefit of a satellite communications network lies in its ability to link users to voice, video and data information where other forms of terrestrial networks may not be feasible. The advantages and disadvantages of this form of communication are highly dependent on the satellite and network configuration.
Typical networks are described as one-way or two-way. In a one-way network, the communication originates at the remote transmitting terminal. It is received and re-transmitted from the satellite to the network operations center or hub. From here, the signal is re-transmitted to the satellite and then to the remote receiving terminal. This type of communication is known as “double-hop” and the network topology is called a star. The hub provides the central routing and switching functions of the network between the satellite and remote terminals, as well as command and control of the satellite itself.
A network can also be configured so the remote terminals bypass the hub and communicate directly with each other through the satellite. This is called two-way communication and the satellite network is in a mesh configuration. In this case, the hub only provides monitoring and control functions to the satellite.
A satellite will use an array of transponders to translate the uplink signal from the ground to a lower frequency for the downlink transmission back to the ground terminals. This frequency shifting technique reduces interference and feedback and the resulting architecture, is known as“bent pipe” architecture, that also helps reduce the cost and complexity of the satellite. Typically, the terminals, gateways and network operations center must be within the coverage of the same beam.
To meet ongoing requirements for global coverage coupled with a move towards higher bandwidth requirements has resulted in networks being operated at higher frequency underpinned by satellites that feature greater onboard functionality. Such satellites feature sophisticated on-board processors (OBP), switch matrix and phased array technology to place the routing intelligence in the satellite. This allows the ground terminals to communicate directly with one another rather than every transmission going through the network operations center.
Figure 1. Satellite Communication Network Topologies.
These single-hop mesh networks offer greater available channel bandwidth and more efficient modulation schemes with onboard satellite processing and electronics allowing the networks to be comprised of many smaller spot beams to target usage areas more efficiently. These spot beams link in a mesh architecture where terminals in any two beams can communicate with one another directly. This enables frequency re-use and dynamic allocation of bandwidth among beams.
Satellites communications use several standard nomenclatures to reference operating frequency. The common International Telecommunications Union (ITU) designation of satellites frequencies of operation are classified as UHF, SHF and EHF.
- Ultra High Frequency (UHF) - 300 MHz - 3 GHz range
- Super High Frequency (SHF) - 3 – 30 GHz
- Extremely High Frequency (EHF) in the 30 – 300 GHz
The most commonly used frequencies for satellite communications can also be categorized using IEEE nomenclature. In addition to the C-, Ku- and Ka-band frequency bands, military satellite systems also make extensive use of X-band communications frequencies. While the nomenclature “C-band”, “X-Band”, “Ku-band” and “Ka-band” are used universally, the frequency range used depends on the area of the world and end usage with the actual frequency ranges often classified to make them more difficult to disrupt.
Figure 2. IEEE Frequency Designations.
Military satellite communications have typically focused on C-band and X-band operations, but as use of satellite terminals has increased, so these bands have become increasingly capacity constrained and increasingly expensive. Bandwidth demand over the years has increased driven in part by continued growth in intelligence requirements and the expansion of UAS platform usage to incorporate BLOS (beyond line of sight) operations. This has led to the use of systems operating at higher frequencies such as Ku-band and Ka-band.
The use of Ka-band for military satellite communications in particular has received growing attention as the frequency band offers a number of benefits which include:
- Higher upload and download data rates
- Better spectral efficiencies
- Less congestion in the spectrum band
- Lower bandwidth costs for the user
Furthermore, antenna gain is proportional to area and frequency, so higher operating frequencies translate to smaller antennas for the same gain enabling smaller satellite terminal equipment and pushing the concept of COTM/SOTM (communications on the move/satellite on the move) into the hands of individual soldiers. The narrower beam width of a higher frequency signal allows for more and narrower spot-beam operation which can be further enabled through the use of phased arrays.
These trends will support the continued use of military satellite communications (milsatcoms) as key enablers in completing the C4ISR jigsaw and acting as critical nodes in the net-centric communications environment. This is reflected by the broad range of terminal solutions available, targeting requirements across the land, air and naval domains.
The Milsatcom Terminal Supplier Landscape
The following graphic provides an illustrative snapshot (and is by no means exhaustive) of some of the companies that are active in supplying military satellite terminals to the defense sector.
Figure 3. Milsatcom Terminal Supplier Landscape
Land-based systems can be categorized based on size and mission (strategic vs. tactical) and incorporate fixed and transportable systems, mobile/vehicular-based systems and portable and dismounted form factors.
- Elta Systems ELTA’s ELK-1895 is a full duplex lightweight transportable tactical SATCOM terminal that is designed to be transported and operated by a single soldier.
- The Low Cost Terminal (LCT) is an industry-funded terminal which takes advantage of Northrop Grumman and Lockheed Martin system knowledge alongside Comtech TCS to provide Protected Communications on the Move (P-COTM) and Protected SIPR/NIPR Access Point (P-SNAP) communications at the halt capabilities with a focus on supporting communications over the AEHF (Advanced Extremely High Frequency) satellite network.
Airborne military satellite terminals are used across a broad range of platforms including combat aircraft, special mission platforms, helicopters and UAS.
- Viasat offers a broad range of terminals designed to cover the full complement of airborne missions. The Ku/Ka-band VMT-1220HM airborne satellite terminal is designed for COTM on C-130 platforms, and the company also offers terminals for light aircraft as well as helicopter platforms.
- Airbus offers the AirPatrol satcom terminal which is designed to be installed on fixed wing, rotary wing or UAS platforms and can be configured for operation across X, Ku or Ka frequency bands
Military satellite terminals in the naval domain span the full spectrum of platforms both surface and subsea, including aircraft carriers, destroyers, corvette, frigate platforms as well as the emerging demand from USVs (unmanned surface vehicles).
- Raytheon’s NMT (Navy Multiband Terminal) is expected to be installed in approximately 300 U.S. Navy ships, submarines and shore stations, replacing several existing SATCOM systems. NMT variants offer X-, Ka- and Q-band, enabling communications across current and legacy US military satellite communications networks including AEHF, Milstar, Ultra High Frequency Follow-on (UFO/E/EE), Interim Polar, Enhanced Polar System (EPS), Defense Satellite Communications System (DSCS) and Wideband Global SATCOM System (WGS).
- Indra offers the TNX-100 terminal which is designed to operate at X-band through through a range of satellites including SPAINSAT, SKYNET, SYRACUSE, SYCRAL and XTAR.
Anatomy of a Satellite Terminal
A satellite terminal can be broken down into a number of constituents, as shown by a representative breakdown of the Norsat GLOBETrekker 2.0 Flyaway Satellite Terminal.
Figure 4. Anatomy of a Satellite Terminal.
From a RF and microwave perspective there a number of core components that enable connectivity in a satellite terminal.
- A BUC (block upconverter) converts a band of frequencies from a lower frequency to a higher frequency and is used in the uplink.
- An RF power amplifier which provides the power amplification of the signal.
- The LNB (low-noise block downconverter) is used in the receive path of a transmission, and typically combines a LNA (low-noise amplifier), as well as other components to that enable the received signal to be down converted for the modem.
The above is an extreme oversimplification as demonstrated by the block diagram shown in Figure 5, which shows some of the other components that make up a satellite terminal system.
Figure 5. Qorvo Block Diagram of a Multi-Band VSAT
Requirements for higher data rates with a focus on IP-centric communications that encompass video and data as well as voice will push demand for military satellite terminal systems. Communicating securely faster over multiple channels and wider spectrum in an increasingly complex spectrum environment will underpin the current and future trends for system design architectures which will dictate the underlying changes in component technology demand.
This will be especially true for the RF power amplifier where the choice between vacuum tube-based solutions based around klystrons and TWT (travelling wave tubes) based power amplifiers has been expanded over the years to encompass SSPAs (solid-state power amplifiers). This latter category has fragmented further with the maturation of GaN technology offering an alternative to both vacuum tube and GaAs-based solutions.
Strategy Analytics forecasts that the global military satellite terminal market will grow from $4.3 billion in 2016 to reach $6.2 billion in 2026, a CAGR of 3.6%. The total number of satellite terminal shipments is forecast to grow at a CAGR of 3.7% through 2026 to reach 8,376 units from 5,829 units in 2016.
Figure 6. Military Satellite Terminal Market Outlook.
Land-based satellite terminals will continue to represent the largest market both in dollar as well as shipment terms, with the segment forecast to account for 49.7% of the total satellite terminal communications spend and 77.0% of total shipments in 2026. The market for airborne satellite terminals is forecast to grow the fastest, from $1.0 billion in 2016 to $1.5 billion in 2026, at a CAGR of 4.0%. Shipborne military satellite terminal communications system demand will grow at a CAGR of 3.1% to be worth $1.6 billion in 2026.
While the traditional frequencies including C-band and X-band will remain a staple component of satellite communications, bandwidth constraints and a push towards higher data rates focused on IP-centric communications that encompass video and data as well as voice will push demand for military satellite terminal systems operating at higher Ku- and Ka-bands with the subsequent market for systems operating at these frequencies forecast to grow at a CAGR of almost 5% through 2026. This will be coupled with the emergence of multi-band/wideband capable systems to enable true global roaming capabilities.
Military Satellite Terminal System Component Trends and Outlook
Communicating securely at faster rates over multiple channels and wider bandwidth in an increasingly complex spectrum environment will underpin the current and future trends for system design architectures which will dictate the underlying changes in component technology demand. In general, these can be distilled into four key issues that are largely in common with the other military and commercial technology sectors. These include dealing with a growing data tsunami, identifying the optimal technologies from the antenna to the baseband, bridging the energy gap to allow equipment to be SWaP-optimized and recognizing the increasing demands that will be placed on semiconductor performance as the emphasis shifts towards higher frequencies and broadband performance.
- Communications are no longer confined to voice transmission, but are focused on IP-centric delivery of data in a wide range of formats including video, imagery, messaging with the delivery of voice now also moving into the IP-based domain. This increasing use of data translates into ever larger chunks of bandwidth being consumed at faster and faster rates. As spectrum becomes an increasingly sparse resource, dealing with this data tsunami across military communications is tightening up the requirements for better spectrum management. Optimizing spectrum use will require use of more complex modulation while the use of AESA-based architectures will also migrate into satellite terminals longer term.
- At the RF front-end, satellite terminals will take increasingly take advantage high power wideband RF technologies that can bridge the traditional gap that has existed between solid-state and vacuum tube technologies. Similarly, the receive side will be underpinned by wideband receive capabilities, coupled with bringing the signal into the digital domain using faster ADCs and DACs to enable faster digital processing.
To meet these challenges, military satellite terminals will see increasing use of solid state technologies. These solutions were initially based around GaAs technology and offered potential advantages over vacuum tube based solutions in terms of cost and size with power outputs reaching 100 to 200 W. As GaN technology has matured, so SSPAs based on GaAs are being displaced by GaN solutions that can offer higher power and greater linearity enabled in smaller form factors.
The caveat is that despite solid-state semiconductor technologies such as GaN seeing increasingly robust adoption, a continued emphasis on high power, long range communications, especially in the shipborne military satellite terminal market, as efficient performance above 200 W at X-, Ku- and Ka-band frequency bands remains a differentiator for vacuum tube based RF power amplification. However, the performance attributes of GaN are now enabling solutions that offer power outputs that start to approach TWTA levels. This will mean that while existing equipment repairs and retrofits will maintain a market for vacuum tube-based components, the emphasis moving forwards will shift towards solid state solutions
The trend towards solid state solution based offerings is being reflected in the offerings from major suppliers of BUCs and SSPAs supporting the satellite terminal market.
- Advantech Wireless offers a complete line of GaN-based SSPA, Solid State Power Block (SSPB) and block upconverters. At X-band, for example, the company’s SapphireBlu™ series of GaN-based products offer power levels reaching up to 600 W.
- Communications & Power Industries (CPI) has offered solid state amplifiers for over four decades, and has been increasingly focusing solutions on GaN technology to replace the company’s GaAs-based offerings. For example, the company’s C-band 100W GaN-based Model 4710H offers over 35% reduction in weight over the GaAs-based 7720H 100W C-band GaAs BUC, as well as offering reduction in volume and an increase in efficiency. The company has detailed even better performance metrics when comparing Ku-band solutions whilst using GaN for Ka-band has yielded the Model B5KO which offers four times the output power of the previous generation of GaAs amplifier.
- Norsat is also developing solutions based on GaN with its Atom series of Ku- and Ka-band series of products citing several benefits that include reduced production price, low conductance losses due to low resistance, quicker devices yielding fewer switching losses, lower power requirements and smaller devices. Furthermore, Norsat’s comparison of Ka-band GaAs-based versus GaN-based offerings, find GaN offering advantages in other parameters such as ACPR (spectral regrowth) and TTIM (two-tone intermodulation).
There are numerous other companies that are actively pursuing the benefits of GaN over GaAs-based solutions including Comtech Xicom, General Dynamics and Mission Microwave and are offering solutions for the military satellite terminal market.
The primary benefits of GaN technology can be distilled down to several primary attributes:
Strategy Analytics forecasts demand for high power RF and related semiconductor components and technologies through to the digital backend from the military satellite terminal market will grow at CAGR of 1.7% from $175 million in 2016 to reach $206 million in 2026, and the increasing use of solid-state technologies will translate to the penetration of GaN technology growing by over 500% through to 2026.
Conclusions and Implications
Strategy Analytics forecasts spending on global military communications systems and services will grow to over $36.7 billion in 2026, representing a CAGR of 3.5%. Satellite communications will account for 37.2% of this opportunity. These trends will support the continued use of military satellite communications (milsatcoms) as key enablers in completing the C4ISR jigsaw and acting as critical nodes in the net-centric communications environment. This is reflected by the broad range of terminal solutions available, targeting requirements across the land, air and naval domains.
Communicating securely and faster over multiple channels and wider spectrum in an increasingly complex spectrum environment will underpin the current and future trends for system design architectures which will dictate the underlying changes in component technology demand. At the RF front-end, satellite terminals will take increasingly take advantage high power wideband RF technologies that can bridge the traditional gap that has existed between solid-state and vacuum tube technologies and this is encapsulated in the attributes offered by GaN technology.
Strategy Analytics forecasts the penetration of GaN technology will grow by over 500% through to 2026. This represents a growing opportunity for GaN semiconductor technology suppliers including Northrop Grumman, Qorvo, Wolfspeed, a Cree Company, UMS and Win Semiconductor. Companies that succeed in this market will need to combine the linearity, power and efficiency offered by GaN into MMIC-based solutions offered in cost effect packaging that enables the continuing requirements for smaller sized and lower weight satellite terminals.