LESAF project proposed a low-profile and highly efficient Electronically Steerable Antenna (ESA) solution for In-Flight Connectivity services. This was achieved by next breakdown of activities:
1. Requirements definition
2. System analysis
3. Technology assessment
4. Demonstrator
5. Validation
Initial stages of the project were focused on the definition of the requirements and system analysis. Considering the In-Flight scenario, a study was performed with regard the electrical performance and regulatory/mechanical/environmental normative. Key features were defined as key: Ka-band operation, high scanning range, multibeam capability, low profile/drag and high reliability.
The technology assessment activity was divided into researching and breadboarding tasks. A thorough investigation of steerable antenna architectures was performed, from approaches based on digital processing to RF beamformers and radiating elements. Candidate technologies were considered for breadboarding stage, so the assessment of several key concepts was carried out. As result, most promising ones were selected to define and develop the demonstrator, particularly at radiating element and RF beamforming level.
As part of the demonstrator activity, TX and RX hardware were developed to integrate and validate the proposed. Both demonstrators, medium-scale apertures, were conceived with significant complexity and performance to validate the LESAF approach.
On one hand, TX Demonstrator consisted of a 32x48 radiating elements full aperture in Ka-band including M&C, cooling system and RF distribution stages. It was reconfigurable to provide flexibility in the activation pattern of antenna. On the other hand, RX Demonstrator was a 32x64 radiating elements full aperture in K-band with the ability of operating as single and dual apertures. Manufacturing, Assembly, Integration and Testing tasks were carried out during this activity. The key results on Demonstrator are summarized below:
• Frequency range: 27.5-30.0 GHz in TX, 17.7-20.2 GHz in RX
• Channel bandwidth: 100 MHz in TX, 500 MHz in RX
• Low power consumption, High EIRP, High Directivity
• High Scan angle range [0º-70º]
• Radiating patterns: High matching to simulations
The validation activity was intended to test extended functionalities of the demonstrators. Essentially, the smart reconfiguration in TX and multibeam operation in RX. But also, the behaviour of beam pattern, eirp, directivity and consumption in the different configurations. The test was performed by using the high degree of flexibility that TX and RX demonstrators offered. As result, it was observed the high potential of the proposed techniques to enable multi-beam and to improve link capacity at worst-case scan-skew angle combination.
LESAF project achieved active involvement in dissemination, communication and exploitation activities. A broad audience was addressed by means of different channels, like project website (
http://www.h2020-lesaf.eu/(s’ouvre dans une nouvelle fenêtre)) publications in magazines and in conferences (EuCAP’22, TSAS’222), participating in workshops (EuMW’22) and exhibitions (SatShow’22, IBC’22). As part of the exploitation task, the acquisition of new skills and capacities, consolidation of processes and the development of the demonstrators brought the strategic alliance of TTI and Celestia-UK to a leading position in electronically steerable antenna technology. New contacts with integrators, service providers and aircraft manufacturers showed this trend. Finally, the application for patent was one of the project results that addresses high performance antennas in combination to specific control techniques. The usage of this solution cover In-flight applications but other scenarios might be benefited.
