Project Overview

The ATOS project will develop and qualify a new generation of X band T/R modules, based on GaN HEMT and SiGe BiCMOS technology, with innovative packaging techniques that minimize the footprint, and will integrate a set of T/R modules in a demonstrator of a high-efficiency densely populated AESA tile to be verified in radiated tests.
Such development will enable future space-borne AESA radars at X band with at least a 3x leap in bandwidth, power density and/or azimuth steering capability with respect to current SAR AESAs developed in Europe, and will also enable or drastically improve compact solutions based on array-fed large unfurlable reflectors on small platforms.
The ATOS project will build or consolidate a fully European supply chain including semiconductor technology providers, SMEs and academia as design centers and test houses, and a large enterprise as integrator of space-grade equipment up to turnkey space systems. The components of such team will broaden the scope of their competences through the project, enabling them to be candidates for future developments in related projects and applications in commercial space as well as institutional programs.
The ATOS advancements achieved will be disseminated to foster initiatives of new mission concepts and business opportunities, specifically but not limited to Earth Observation, for which results of the project may represent a key technology enabler.

Mission Scenario and User Needs
The roadmaps of satellite-based SAR systems show a trend that requires a continuous improvement of the Active Antenna in terms of
• operating bandwidth – a principal contributor to the resolution in the Elevation plane;
• scanning angle capability – with a request to increase the scanning angle thus resolution in the Azimuth plane, leading to more flexible operating modes.
• swath width – with a request to increase the coverage for a given resolution

The larger operating bandwidths for a given antenna aperture, and/or operation at larger swath widths for a given desired resolution, will lead to a corresponding request for
• increase of RF power,

in turn implying a need of
• increased power efficiency.

The increase in Azimuth scanning angle leads to a closer proximity of the T/R modules, thus to a need for a higher quantity of T/R modules for a given antenna aperture, implying a request for
• reduced mass,
• reduced cost.

In the case of array-fed reflectors for compact SARs, where the electronic scanning required is limited given the fixed reflector, the benefits of a more wideband, powerful, efficient and compact T/R module remain obvious as this will result in a resolution enhancement and/or in a smaller feed array subsystem.

ATOS Concept Overview
In order to achieve the above stated goals, ATOS foresees
• the conception of a transmit/receive module architecture featuring minimal parts count
• the design and development of high power, highly efficient GaN frontend MMICs operating over the X-band
• the design and development of low-consumption, highly producible SiGe BiCMOS core chip ICs operating over the X-band the design, development and space qualification of a transmit/receive module embedding the above ICs with a minimal footprint, while ensuring adequate thermal management, via ingenious packaging solutions, exploring 3-D vertical stacking of the microwave circuits.
• the design and development of a lightweight, low loss radiating panel operating over the X band
• the design and validation of a structural assembly suited for housing the electronic frontend with proper thermal draining
• the assembly and validation of a demonstrator of the Electronic Front End housing a set of TR modules, fully representative of RF performance, and interconnected to the radiating panel, suited for radiated tests and capable of proving (by scaling the test results) the overall Antenna performance.