PAGE CONTENTS
Objectives
The goal of the BEAMSAT-2 project is to study, design, realise and test a cost-effective high gain antenna, with a goal gain of G ~ 30 dBi, for inter-satellite links between CubeSats.
The application scenario for the intended development is a 59.3-71 GHz inter-satellite link that could operate in frequency-division full duplex or time-division simplex/duplex.
The reference scenario foresees the use of a link between satellites that are in the same orbital plane and separated 2000 – 4000 km from each other; the goal is to obtain a data rate between 1 – 3 Mbps.
The result of the BEAMSAT-2 project is an Axially Displaced Ellipse (ADE) antenna. The system is characterised by a high gain >30 dBi on the overall bandwidth 59.3–71.0 GHz, occupying a total volume <0.5 U, a mass <100 g. The pointing system provides an azimuthal orientation of +/-180°, zenithal orientation: +/- 40°.
Challenges
The key challenges of the BEAMSAT-2 project are technical:
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RF performance: >30 dBi on the overall bandwidth 59.3–71.0 GHz, axial ratio <1.2 dB, sidelobes level <-13 dB;
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Miniaturisation: total volume <0.5 U, mass <100 g;
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Pointing system: azimuthal orientation of +/-180°, zenithal orientation: +/- 40°.
In addition, thanks to the efficient application of 3D printing techniques, the overall production cost is kept very low.
System Architecture
The antenna and pointing system are located inside a CubeSat unit. In order to be able to freely operate the antenna pointing, a deployment system is necessary. For this purpose, we developed a deployment system driven by 4 compression springs.
The system, locked by a mechanical joint, is activated by the rotation of the pointing system base, see figure below (left).
Activating the pointing system by rotating the base of the pointing system (azimuthal pointing) allows one motor to be used for several functions, reducing the mass and number of components used. The great advantage of this solution is certainly the possibility of using the pointing system to activate the deployment system, thus saving in terms of mass, additional components and system complexity. Turning the azimuthal pointing in a counter-clockwise direction releases the mechanical constraint, thus allowing the springs to bring the pointing system and the antenna into its final position.
The figure also shows the deployment system before activation (in the middle) and after activation (right).
Plan
The project is organised in six tasks:
Task1 Finalised Technical Requirements
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Finalised technical Specifications
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Implementation Feasibility
MS1 Requirement Review
Task2 Antenna System Concept and Technology Selection
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Antenna System Concept Review
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Manufacturing Technologies Review
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Proposed Antenna System Solution
Preliminary Design Review
Task3 Antenna System Detailed Design & Analysis & Prototype
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Antenna System Thermal and Mechanical Design
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Antenna System Detailed RF Design
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Sensitivity Analysis
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Antenna System Prototype Design
MS2 Critical Design Review
Task4 Antenna System Prototype Manufacturing
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Manufacturing Subsystems
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Assembled Prototype Antenna System
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Test Procedures
Prototype and Test Readiness Review
Task5 Antenna System Prototype Testing
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Tests of Antenna System Prototype
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Update Antenna Prototype
Task6 Antenna System Development Plan
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Overall Evaluation
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Antenna System Development Plan
MS3 Final Review
Current Status
The BEAMSAT-2 project is aimed at designing, producing and testing the prototype of a “Cost-Effective High-Gain CubeSat Antennas”. Currently, the first five tasks are accomplished, tests confirmed the positive results of the simulations.
The last task is aimed at providing the overall evaluation, the roadmap and the antenna development plan. We identified several potential additional antenna solutions and applications that can profit from the BEAMSAT-2 results. PICOSATS is now looking towards the engineering of the full system, especially of the pointing system, to arrive at a launch opportunity. In order to achieve that, PICOSATS is also planning to develop a transceiver working at these frequencies.
