Ka-band GaN-based SSPA for flexible payloads and multicarrier operation for 5G satellite concept

Project Information

FLEXGAN

Grant agreement ID: 821830

DOI

10.3030/821830

Project closed

EC signature date 19 October 2018

Start date 1 November 2018

End date 28 February 2023

Funded under

• INDUSTRIAL LEADERSHIP - Leadership in enabling and industrial technologies – Space

Total cost

€ 2 133 410,00

EU contribution

€ 2 133 410,00

Coordinated by

TTI NORTE SL
Spain

Periodic Reporting for period 3 - FLEXGAN (Ka-band GaN-based SSPA for flexible payloads and multicarrier operation for 5G satellite concept)

Reporting period: 2021-11-01 to 2023-02-28

Summary of the context and overall objectives of the project

5G demand requires the deployment of very High Throughput Satellites (vHTS) than can satisfy the expected needs implying a growth opportunity for GEO satellites. This kind of spacecraft offers high capacity, large number of users and communication volumes (1 Terabit/s per satellite), with lower cost per GBPS, increasing the flexibility since the satellite capacity is allocated where needed. Future vHTS satellites will use Ka/Q/V gateways where the forward payload link will operate in K-band. Traditionally, demand for power at high frequencies has resulted in Travelling Wave Tube Amplifiers (TWTAs) as the logical amplifier choice. However, technological advancements such as linearization, miniaturisation, and the use of different materials such as Gallium Nitride (GaN), have levelled the playing field for SSPAs.
The project Ka-band GaN-based SSPA for FLEXible payloads and multicarrier operation for 5G satellite concept (FLEXGAN) aims at designing, developing and testing, in a representative space environment (TRL5), a low cost high power and efficient Ka-band Gallium Nitride (GaN) Solid State Power Amplifier (SSPA) with RF output power varying capability (flexible SSPA), with high innovative & low loss recombination schemes and with the ability to operate in multicarrier operation mode for highly flexible payloads for 5G satellite applications. The operational frequency band is 17.3-20.2 GHz and the target output power is 125 W CW.
The objectives of FLEXGAN are:
• Objective 1: Establish specific requirements for the design and development of a GaN based SSPA able to operate in Ka-band satellite networks for future 5G connectivity
• Objective 2: Design, develop and test an EM SSPA based on non-EU technology. The idea is to have in a first phase a SSPA that could be fully characterised and useful to demonstrate key challenging aspects of the design of an EM SSPA fully representative of a FM configuration. As an output of objective 2, aspects such as multipaction, corona effects, thermal dissipation, output power flexibility and high efficiency combination will be fully designed and tested in the phase 1 of the project
• Objective 3: Design and test a MMIC based on European D01GH GaN technology from OMMIC
• Objective 4: Upgrade the EM SSPA (objective 2) using the MMICs from OMMIC (objective 3) and perform environmental tests in order to have at the end of the activity a TRL5 SSPA. All the research findings and results of FLEXGAN that don’t compromise the future exploitation activities will be disseminated and communicated to the scientific and industrial community as well as to the general audience

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

FLEXGAN Product Assurance plan was defined and detailed specifications established. Baseline SSPA architecture was defined, and Design Verification Matrix issued.
Two highly efficient combining techniques were evaluated, obtaining good matching between simulations and tests.
5G SSPA was designed, from the high-level description to the design of every subsystem. Each one was manufactured and validated before its integration in the mechanical subsystem, a composite enclosure with thermal and mechanical performance validated by simulations.
First EM SSPA (based on non-EU MMIC) was integrated and tested following the verification plan defined. Excellent performance in linearity (NPR figure), efficiency and output power were measured in 1.25GHz of bandwidth, at the middle of FLEXGAN band. Many conclusions were drawn to apply to next upgrade.
Two iterations of GaN MMICs were designed, manufactured and tested, based on OMMIC technology. Two first-run MMIC models were submitted to extensive tests (on special test-jigs) which data were used as baseline for the retrofit of the second-run iteration, being designed four models which on-wafer results shown outstanding output power and efficiency characteristics, improving their performance compared to first-run. Among them, AKILOS2 was selected as baseline for the SSPA upgrade according to test-jigs results, showing higher output power than 10W and peak PAE values of 36%. The MMIC has been incorporated at OMMIC website (as DEV2642UH).
Upgraded SSPA (based on AKILOS2) was designed considering previous experience. All subsystems were manufactured and validated, highlighting innovative variable output voltage GaN based PSUs, power modules based on AKILOS2 and a lighter composite enclosure. This SSPA was submitted to a complete test campaign, including NPR, improving by far first SSPA performance, fulfilling most of requirements and showing outstanding power, linearity and PAE results in whole operating band. It was submitted to reliability tests, including mechanical&shock, thermal and vacuum, and EMC, which were successfully passed, demonstrating its ability to operate in space environments, reaching TRL-5 level.
Multipactor and corona simulations were performed, showing that FLEXGAN SSPA is free of both phenomena.
Significant efforts were devoted to the communication, dissemination and exploitation. Communication activities were focused on the project public disclosure and its objectives. Several scientific contributions based in the most noticeable project achievements as combining techniques, designed MMICs or FLEXGAN SSPAs results were accepted at prestigious international events. A workshop was organized, and two flyers designed for publicising FLEXGAN achievements.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

FLEXGAN supposed disruptive innovation because it changed the nature of competition in the marketplace and lead to the creation of new ventures. Its innovation relied on the development of a novel, fast and cost-effective high power SSPAs based on GaN technology, which are able to provide the same services as TWTAs but with other benefits such as graceful degradation, lower supply voltages, lower cost and better integration (after adapting it) in case of phased-array and multi-spot systems.
FLEXGAN SSPAs represent a new advance in the application of GaN solutions to spacecraft payloads, helping to eliminate the gap in application of GaN technology to space models.
They are specifically geared towards a Flight model to be used on board the next generation vHTS satellites to be deployed in the 5G ecosystem. Satellite systems are key components to provide 5G services, augmenting their capability and addressing some of the major challenges: increasing connectivity and reducing cost per bit. FLEXGAN SSPAs promoted to the integration of satellites communications into 5G, enabling reliable and flexible amplification of the 5G signal within satellites, 'key' to allow access to broadband internet access anywhere/anytime. Also, they led to reducing the CAPEX and OPEX in the 5G radio networks.
FLEXGAN contributed to increase the competitiveness of the different stakeholders in the European Space industry and created new business opportunities. Thanks to the achievements of FLEXGAN, different products based on GaN are able to be developed for the space market, either for the space or ground segment. FLEXGAN technologies can be also applied to ground products in commercial and military markets. The technology allows spin-off products for being installed in hub stations and user terminals.
New job opportunities were created, promoting the growth of technical qualified employment. FLEXGAN stimulated the integration of space into European society and bring benefits to European citizens. Also, it contributed to European research and technology ecosystem.

FLEXGAN Consortium

FLEXGAN Phases