PAGE CONTENTS
Objectives
Project Goal
To design, manufacture, and test a reduced-complexity, sparse Ka-band electronically scanned antenna breadboard for ground terminals, enabling seamless connectivity with satellites across multiple orbits.
Specific Objectives
Cost-Effective Design: Develop affordable antenna solutions tailored for next-generation satellite communication (SatCom) ground terminals;
Architectural Innovation: Synthesize modular antenna architectures utilizing advanced element-level and subarray-level controls;
Feeding & Efficiency Optimisation: Simplify the beamforming network by minimizing the number of beamforming integrated chips (BFICs) while simultaneously maximizing DC-to-RF power efficiency;
Advanced Manufacturing Integration: Design innovative single and clustered antenna elements optimized for fully-metal 3D printing.
To achieve these objectives, the project will evaluate and trade off various sparse array configurations and beamforming network topologies. The final phase will encompass the complete design, manufacturing, and experimental testing cycle to validate the feasibility of the architecture and ensure full compliance with target performance requirements.
To achieve these objectives, the project will evaluate and trade off various sparse array configurations and beamforming network topologies. The final phase will encompass the complete design, manufacturing, and experimental testing cycle to validate the feasibility of the architecture and ensure full compliance with target performance requirements.
Benefits
The investigated solution implements a reduced-complexity Ka-band electronically scanned antenna breadboard suitable for advanced satcom ground terminals. These antennas are currently expensive compared to conventional electronically scanned antenna systems. In particular, the number of radiating elements increases significantly when a wide field of view and broad operating bandwidth are required. In such cases, tiled or subarrayed structures can be adopted to reduce the number of amplitude and phase control points.
Compared to existing technologies, the SKYBEAMS array is based on an irregular partitioning of the aperture using polyhex tiles, which break the periodicity of the amplitude and phase quantisation across the aperture. This approach can significantly reduce the level of secondary lobes over wider bandwidths and scan ranges compared to regularly partitioned antenna arrays.
Furthermore, recent technological advances in integrated circuits have enabled the development of antennas with simplified and more compact beamforming networks. Consequently, commercially available technologies have been considered and integrated with the optimized array architecture, resulting in a highly modular and scalable solution.
Features
The Ka-band phased array comprises circularly-polarized radiating elements. A notable achievement is a reduction in the number of BFICs greater than 30% as compared to a fully-populated array solution, including an independent amplitude and phase control for each antenna element, achieved by grouping elements into tiles controlled by a reduced set of chips.
Moreover, the architecture incorporates multiple levels of modularity, simplifying the implementation of the beamforming network. To ensure continuous connectivity with different orbit satellite constellations, the array is optimized to meet gain, scan loss, and sidelobe requirements for scan angles up to 70 degrees.
Challenges
The main challenges addressed in the project include:
(i) the identification and optimisation of a highly modular array antenna architecture, aiming to simplify the beamforming network;
(ii) the design of polyhex subarray configurations for large arrays with specific constraints, including a reduction in the number of control points, limited scan-loss, and grating lobes avoidance;
(iii) the optimization of circularly-polarized radiating elements to meet the requirements for wide scan and Ka-band bandwidth in modern satellite applications.
System Architecture
The array architecture features element-level and subarray-level controlled antenna elements and multiple levels of modularity. In the subarrayed part, the radiating elements are grouped into polyhex tile modules that share the same amplitude and phase excitation. This approach reduces the number of amplitude and phase control points, lowering costs associated with additional control chips, minimizing the physical space required for the beamforming network, and reducing weight and power consumption.
The tiles are further grouped into higher-level modular blocks, which are controlled by beamforming integrated circuits. Finally, these modular blocks are assembled into different panels with varying degrees of irregularity in the tile arrangement.
Plan
Phase 1: Technical specification and baseline definition:
o Survey of the state of the art, critically assessment of available solutions, and definition of the set of technical requirements (Milestone 1);
o Preliminary design for the prototype (Milestone 2).
Phase 2: Detailed design of the prototype:
o Detailed design of the prototype, specifically addressing the radiating part and the beamforming network, ensuring compliance with the technical requirements (Milestone 3).
Phase 3: Breadboard development, testing, and final assessment:
o Manufacturing of the prototype and test campaigns (Milestone 4);
o Analysis of the prototype performance against expectations (Milestone 5).
o Definition of the technology development roadmap (Milestone 6).
Current Status
The technical specification and baseline definition activities have been completed, ensuring consolidation of the system scenario and alignment with the project requirements. The collaborative efforts of the project partners have included a detailed and critical survey of the state of the art, supported by preliminary technical assessments and trade-off analyses, leading to the selection of a sparse antenna architecture consistent with the project constraints.
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