ADF – Antenna Design Framework
ADF makes the difference
Considering the panorama of existing EDA tools, it must be recognized that a further electromagnetic simulator would be almost pointless…
The Antenna Design Framework was designed, in collaboration with the ESA, with the precise purpose of overcoming the limitations of simulators available on the worldwide market in space applications and beyond. Its development was focussed to obtain a true EDA tool for space antenna engineers, something not available in the other commercial electromagnetic simulators.Ever since, the effort has been to keep it unique by continuously adding specific capabilities.
ADF is a simulation environment that brings together validated and sophisticated electromagnetic solvers, a large number of fast tools and functions dedicated to antenna engineers and a rich set of user-friendly modeling procedures.
Through ADF it is possible to produce highly accurate prediction of the electromagnetic performance of single antennas, arrays and complex antenna platforms, thanks to outstanding computational methods and special functions required by space applications and usually not found in general purpose tools.
The effectiveness of the simulation tools integrated in ADF is increased by the data structures and the working procedures implemented in the framework. Through these capabilities, ADF is able to manage the complexity of the design of real antenna systems and the modeling of a realistic satellite.
Therefore not only does ADF simulate models which are larger and more complicated than standard electromagnetic simulators can handle but it also works more efficiently thus reducing the overall design cycle of modern satellites.
Array modeling and design
Many electromagnetic simulators offer full-wave analysis of arrays. However they often have limitations in the maximum size that can be handled on
average computing platforms. The ADF section dedicated to “Arrays” features full-wave tools with outstanding performance allowing the modeling of structures with hundreds of thousands of mesh elements in just a few minutes on standard PCs. But this is only part of the full story: much more is needed in the daily work of array designers. ADF offers a large set of special functions to assist Users along the complete design process, from conception to final verification of the product:
- a dedicated array CAD tool to create complex layouts and to manage excitation laws, sequential rotation
- tools to define the initial array layout and excitation based on unconstrained and constrained synthesis of equivalent apertures from pattern requirements
- modeling procedures at different complexity and accuracy levels: isotropic elements, element pattern from measurement or simulation, full-wave modeling of the whole array (including inter-element coupling) and more
- a versatile optimizer with both global and local optimization algorithms
- companion tools for sensitivity, failures and scan blindness analyses
- the capability to “reduce” array models to allow the efficient analysis of their performance when installed on a platform
- innovative methods for fast and accurate full-wave analyses (MoM/SIM, SFX, SM-AIM… multilayer Green Functions…)
Antenna siting, RFC Analysis
ADF-EMS has been conceived to make analysis and optimization of antenna placement on large platforms an integral part of the design process, with special reference to satellites.
From IDS’s experience in “platform system integration” we know that a good full-wave modeler doesn’t entirely solve the problem. Rather, different capabilities are needed: more than one solver to accurately cover wide frequency ranges and allow cross-checking of predictions, CAD and meshing tools, smart functions to import and to elaborate manufacturers’ antenna data (often incomplete) and tools for data processing. ADF-EMS puts all of that at one’s disposal:
- sophisticated CAD, cleaning and meshing tools
- a palette of 3D simulation methods, parallelized on shared and distributed memory platforms (OpenMP, MPI):
- Method of Moments (MoM, MoM/SFX, MoM/MR, MLFMA)
- Physical Optics (PO/PTD/ITD),
- Uniform Theory of Diffraction (UTD)
- Mixed methods
- a library for material characterization
- a scalable antenna modeling strategy that allows using: patterns, Spherical Wave Expansion, Huygens (equivalent) currents, meshes…
- capability to import external antenna models
- a palette of methods for antenna coupling calculation: S-parameters, Reaction integrals, Generalized Frijs formula…
- on-mesh visualizations, diagnostic ray tracing, plot-onEarth, G/T …
Special modeling for space applications
Most electromagnetic simulators are designed to be general purpose tools.
The obvious disadvantage is that their applicability and efficiency is limited in comparison with dedicated solutions when specific and complex problems need to be solved. ADF-EMS has been developed balancing general capabilities with specific computational modules and procedures to efficiently solve complex problems typical of space applications:
- procedures to enable the analysis of complex antennas (e.g. arrays) by means of “reduced” models based on the equivalence principle
- analysis of the effect of plasma plumes, emitted by ion thrusters mounted on spacecraft, on radiation performance of antennas (blocking effects, pattern distortion, spurious modulation of RF signal)
- analysis of antennas installed aboard re-entry vehicles; blocking and distortion effects of the high temperature plasma cloud; computation of the channel transfer function between vehicle and ground stations during their whole trajectory
- RE-RS analyses inside a spacecraft bus based on the Oversized Cavity Theory (Power Balance Method)
- full-wave optimization of performance of multi-functional and structural antenna systems on spacecraft
- multi-method analysis of the interactions among feeders and reflectors
- risk analysis and control for Passive Intermodulation Products (PIM)