The Wild West: The New Frontier of Flat Panel Antennas

Flat panel antennas (FPAs) have been a popular, and technologically necessary, addition to the satcom ground segment. Serving the needs of new space, multi-orbit strategies, and customer demand, the technology provides capabilities beyond those achieved with traditional parabolic antennas. Megaconstellations in Low-Earth Orbit (LEO) deliver complex challenges due to altitude, with satellites being passed from gateway to gateway as they move to ensure continuous service. Additionally, the ability to connect to multiple satellites at once, sometimes within different orbits means that the phased array element of FPAs drives the market’s need for the technology.

This is reflected in the figures: the global flat panel satellite antenna market was valued at $56.53 million in 2022 and is expected to expand at a CAGR of 52 percent during the forecast period, reaching $695.33 million by 2028.

Satcom is in the midst of a revolution; it is now considered affordable and accessible for the regular member of the public while able to deliver multi-orbit connectivity for those with complex communication needs. With a huge shift in its usual revenue streams, not only is the satcom industry looking at new ways of delivering low-cost, high-quality services to end users, it is looking sideways for new industries to serve, and this includes its sibling industry: telecom. Interoperable software-defined networks will see new opportunities arise, with the network of networks shaking up where potential business cases lie.

This cauldron of change is important to consider, as we see operators and manufacturers tighten their belts in an understandable move to tread the line between innovation and profitability in an unstable, but optimistic, time. However, with changing attitudes as to what will be accepted on operator networks and a drive to keep costs down during antenna manufacturing and testing, are we running the risk of entering into the Wild West of antennas?

The Technical Differences of FPAs

The first thing to consider is how differently FPAs function from parabolic offerings. The flat panel terminal, phased array offerings rely upon multiple antennas to create a high-gain beam which can be electronically steered to point in different directions without having to move the terminal. These beams are bi-directional, meaning they can both transmit and receive. Terminals can connect to multiple satellites at once, unlocking the potential of new space – enabling the tracking and handover of multiple lower altitude satellites while connecting to satellites in different orbits. However, beside unique capabilities lie unique challenges. The scan angle brings challenges to FPA technology. When pointing low on the horizon, the terminal appears near parallel to the satellite and therefore receives far fewer signals than if the satellite is overhead. This directly impacts throughput and performance.

Not All Antennas are Equal

As we witness a surge of FPAs utilization, we are also seeing a concerning shift in attitudes towards a longstanding problem within the industry. Radio frequency interference (RFI) has long plagued satcom, with the shared resource of spectrum being at the center of the battle. An entire industry is reliant upon a resource which is easily influenced by other users, with RFI sporting a hefty price tag, both financially and – importantly – reputationally. Incidents of RFI can result in a reduction in throughput, poor/interrupted services, and even complete downtime. While satcom is facing fierce competition across the communications landscape, reliability and cost efficiency is paramount in maintaining the technology as a popular offering.

Historically, one of the most common causes of RFI has been the utilization of poor quality antennas. In 2019, GVF worked alongside satellite operators to produce updated guidance to antenna manufacturers regarding the satellite operators’ expectations for new antenna products and how to demonstrate compliance with the satellite operator minimum performance specifications (SOMAP). This has meant that manufacturers are able to ensure that the quality of their products matches the expectations of operators. Type approvals have streamlined the onboarding process of antennas onto satellite networks and helped to reduce the number of RFI incidents across the landscape, while simultaneously improving throughput and customer experience.

However, applying the same strategy to FPAs has not been met with the same enthusiasm. It has been widely agreed throughout the industry that there runs a significant risk of networks being flooded by cheap, poorly manufactured antennas in a race to the bottom. Yet there have been endless discussions as to where responsibilities lie, without resolve. There is now hesitancy to refuse poorer performing antennas onto satellites networks due to the financially challenging era that satellite operators face. They continue to prioritize spectrum sustainability; however, warnings of underperformance are handed to customers choosing poorly made products.

The Challenge of Testing a FPA

On the other hand, FPA manufacturers face the challenge of knowing where to draw the line between cost and capability without the guidance of standards. The majority of customers are driven by price and therefore cost efficiency is critical. This is paired with the challenge of testing phased array antennas. FPAs face unique challenges which can have a huge impact on their performance. These include:

Beam Deviation: As the scan angle increases, the beam can deviate significantly, leading to improper exposure of the antenna elements. This can affect the accuracy and quality of the signal/s.

Mutual Coupling: Wide-angle scanning can exacerbate mutual coupling between array elements. This interaction can degrade the performance of the FPA, resulting in reduced sensitivity and increased noise.

Effective Isotropic Radiated Power (EIRP): The number of simultaneously active array elements is often limited, which can constrain the achievable EIRP. This limitation becomes more pronounced at larger scan angles, affecting the overall performance of the system.

Bandwidth Limitations: Ensuring proper illumination and maintaining performance across a wide bandwidth can be challenging, especially as the scan angle increases.

Active Impedance Matching: Achieving optimal active impedance matching performance is crucial for effective scanning. However, this becomes more difficult as the scan angle increases, potentially leading to mismatches and performance degradation.

All of these factors need to be considered during the design phase, where innovative designs and optimization are key, including optimized beamforming methods. However, it’s clear to see how understanding the performance of an FPA is complex, with plenty of room for differing qualities. Antenna testing provides a true picture of performance however it must be determined as to what extent the industry deems acceptable. FPAs differ from parabolic antennas in that the radiation pattern changes depending on the scan angle. By testing at various angles, you can see how the beam deviates and the impact on performance. However, it raises the question: what is the right number of angles to test?

A thorough approach to testing is costly, and the question arises: who should be responsible? Passing the price of testing onto the customer could deter them and lead them to other manufacturers, where, anecdotally, there have been reports of companies producing simulation results as opposed to genuine results obtained via testing.

Promising excellent capabilities on paper without proving performance causes poor customer experience for end users, reputational damage to the industry, a sloppy RF environment riddled with interference, and an unfair market for antenna manufacturers.

The big question is: without accurate and uniform testing, are customers being misled into believing products can perform beyond their actual capabilities? And how can the industry improve transparency to prevent poor customer experience and the wider issues surrounding RFI?

Differentiating Quality

As an industry, we must prioritize mitigating the impact of RFI and doing this truly starts at what equipment we put out there. As satcom positions itself in the wider communications landscape, we must not rush into providing the capability to access satellite services without considering both the quality of service being provided or the unintended consequences of flooding spectrum with clumsy equipment noise.

Industry-wide collaboration is a necessity in defining and identifying high-performing FPAs, through an agreed approach to performance and testing. Low-cost testing technology must be utilized to keep the cost of this process as low as possible. Manufacturers have a significant role to play in the overall picture — they must demonstrate best practices and prove their quality. However, without rules to play by, how can they truly be operating on an even playing field?

As the ones with most influence over the ground segment, satellite operators must also seriously consider their role in this issue. There is a potential long-term consequence of allowing poorer-performing equipment onto their networks: a poor RF environment will have an impact on the quality of services provided. As with any industry, satcom relies heavily on reputation, and could we see a future where satellite operators unintentionally damage their credibility through their interactions with poor quality ground systems?

A SOMAP-type agreement for FPAs could be the solution, however the reluctance from satellite operators speaks volumes. Could this be because they may lose commercial opportunities if they demand minimum performance standards? There is a balance between short-term commercial gain, and long-term reputational pain at stake.

Transparency is imperative. The customer must truly understand what they are buying. Tests must be undertaken to prove compliance to advertised specifications. This will allow customers to choose products based on true performance, resulting in both a better outcome for them but also for the RF environment. However, without improving best practices across the board with set testing criteria, high-quality, conscientious manufacturers could end up being out-priced by those not willing to undertake the same standard of validation. There must be an industry-wide coordinated approach to allow customers to truly understand what they are buying and to ensure that manufacturers are not penalized for spending on testing their products.

Maintaining high standards within the industry is too important to sacrifice on the quest to hand a low price tag to the customer or to secure a large contract. We do not want a race to the bottom. This approach is likely to cause reputational damage to individual organizations, as well as to the industry itself. At a time when satellite faces a raft of new opportunities, as well as competition, it must prioritize quality. Like the age old saying goes: if it is too good to be true, it probably is. The industry as a whole must protect itself from itself. VS

Mark Steel is the director of the Satcoms Innovation Group