Why V-band and W-band matter for SSPAs
Higher, faster, further: Why SSPAs hold the key to high-speed communications at V-band and W-band
By Ashley Dove, Senior Advisor, Filtronic
As demand for high-speed data continues to grow, communications are moving into higher radio frequency (RF) bands to improve performance and escape congestion at lower frequencies. mmWave frequencies such as V-band and W-band offer the bandwidth and data capacity needed for modern communications applications – but require advanced enabling technologies to realise their potential.
In the mmWave frequency range, V-band (40-75GHz) and W-band (75-110GHz) are emerging as hotspots for expanding the possibilities of data communications. One of the critical enabling technologies required to support such high-frequency communications is solid state power amplifiers (SSPAs) – used to boost the power magnitude of signals for transmission over long distances.
SSPAs are compact, efficient, semiconductor-based devices that provide reliable RF power in smaller, lighter packages than traditional amplifiers. Advances in semiconductor technology are enabling SSPAs to move up into V-band and W-band frequencies – supporting the expansion of high data-rate, low-latency communications.
V-band and W-band: opportunities and limitations
The V-band and W-band segments of the electromagnetic spectrum offer significant potential for high-capacity wireless communications. V-band (40-75GHz) offers wide bandwidth availability, with broad contiguous allocations available from 500MHz to more than 5GHz.
W-band (75-110GHz) offers high data-rate throughput, especially at high altitudes or in space – supporting advanced applications like satellite feeder links and high-resolution radar. W-band offers even wider bandwidth availability than V-band. While signals at this frequency are still affected by atmospheric absorption, the effect does not increase as sharply as frequency increases. This allows longer-range links to be achieved with appropriate antenna gain and system design.
The wide spectrum availability in both V-band and W-band is attracting great interest from many sectors, for applications from 5G/6G non-terrestrial networks (NTN), satellite communications (SATCOM), lunar and deep-space Comms to radar and sensing systems.
Why SSPAs matter at higher frequencies
At mmWave, there are significant technical challenges associated with achieving the power, efficiency and linearity needed for effective communications. High power is hard to achieve because transistors don’t perform so well at these frequencies – meaning complex amplifier designs are required to produce strong signals. At these frequencies, amplifiers produce more heat and lose more energy, so keeping components cool and energy-efficient is another key challenge.
SSPAs have long been used to replace traditional travelling wave tube amplifiers (TWTAs) at lower frequencies, but recent developments in SSPA power capabilities mean they can now perform reliably at higher frequencies. TWTAs are well established, reliable and still widely used, but they are complex and time-consuming to manufacture. By contrast, SSPAs can be manufactured quickly and in high volumes, at dramatically lower cost than tube amplifiers. At Filtronic, we have now developed SSPAs capable of operating efficiently at mmWave while delivering the high powers only previously possible with TWTAs. This, along with the reduced size weight, improved longevity, reduced maintenance costs of SSPAs, makes them an attractive, low-cost alternative to TWTAs.
Filtronic has managed to achieve this outstanding performance because we design the device MMICs in-house and are thus not reliant on 3rd party supply of the devices needed for these designs.
Demand driven by satellite communications and 5G
Demand for high-capacity data connectivity is being driven by the satellite communications sector and the 5G backhaul market. The telecommunications backhaul market initially spearheaded the shift from microwave to mmWave frequencies, and Filtronic developed many of the mmWave solutions to support the transition to 5G. Satellite communications technology offers the capability to deliver seamless global connectivity. But as more satellite constellations are launched into orbit, satellite companies must seek out less crowded mmWave frequencies to achieve the necessary high-throughput, low-latency connections.
Semiconductor technology rises to the challenge
Advances in semiconductor technology are supporting the development of SSPAs for high-frequency applications. The semiconductor compound gallium arsenide (GaAs) has long been used in integrated circuits for its performance at higher frequencies. Now, in the push to meet even more demanding performance standards at mmWave, gallium nitride (GaN) has emerged as an alternative – offering even greater power and efficiency within a specific frequency range.
At frequencies between 6GHz and 40GHz, GaN already offers significantly greater power density than GaAs in the same sized device. At lower frequencies, GaN is around twice as efficient as GaAs. Now, these benefits are being extended into higher frequencies, with GaN starting to be deployed at E-band (60-90GHz). Filtronic has developed an SSPA operating at E-band based on GaAs semiconductors, and we are just about to launch V-band GaN amplifiers and a W-band GaAs amplifier.
International focus on mmWave opportunities
The ESA (European Space Agency), FCC (Federal Communications Commission) and ITU (International Telecommunication Union) are actively supporting the development of V-band and W-band technologies for the benefit of satellite communications, 5G networks and defence applications. The aim is to secure a future where high-speed connectivity is ubiquitous, enabling a host of increasingly advanced use cases.
Filtronic is working with ESA under its Advanced Research and Telecommunications Systems (ARTES) programme to develop mmWave products for satellite applications. This includes developing high-frequency sub-systems to support the move into mmWave for both feeder links and inter-satellite communications.
Creating SSPA technologies for next-generation communications
As V-band and W-band become more strategically important for the next generation of RF communications, Filtonic is leading the way in developing the key enabling technologies. We have already developed the Cerus range of SSPAs to provide unmatched power performance at V band (47.2-52.4GHz), at E-band (71-76GHz, 81-86GHz) and at W-band (92-96GHz, 102-114GHz) frequencies. As demand grows for ever-more bandwidth and data capacity, our SSPAs are set to play a central role in unlocking the full potential of V-band and W-band for multiple high-performance applications.
For more information about our range of mmWave components and solutions, please visit our website or speak to a member of our team on +44 (0)1740 618 800.
You can explore our exciting Cerus range of SSPAs here.
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