CHAMP
Understanding CHAMP
3D Waveguide and Feed Chain Analysis
In satellite communication systems, deep-space networks, and radar payloads, the performance of the antenna feed assembly is a critical factor. These assemblies contain complex waveguide networks, including polarizers, orthomode transducers (OMTs), power dividers, and corrugated horn antennas. Simulating these structures using general-purpose 3D electromagnetic (EM) solvers is computationally expensive and slow due to the fine mesh requirements of curved corrugated structures. CHAMP addresses this by using a specialized surface formulation tailored for axisymmetrical and quasi-axisymmetrical feed components.
Developed by TICRA, CHAMP provides a rapid and highly accurate platform for optimizing entire feed networks. It allows designers to define waveguide profiles analytically or import CAD geometries. The software automates the optimization of horn profiles, maximizing aperture efficiency and matching while minimizing cross-polarization levels across the desired frequency band. This specialized approach reduces optimization times from hours to minutes compared to standard finite element or finite integration methods.
Mode Matching and Method of Moments Solvers
The speed and accuracy of CHAMP stem from its hybrid solver architecture, which combines the Mode Matching (MM) technique with the Method of Moments (MoM). For cylindrical and rectangular waveguide sections, the Mode Matching method is utilized. MM solves the electromagnetic fields by matching the waveguide modal expansions at each physical discontinuity along the transmission path, which is an analytically exact and extremely fast process.
For open-boundary regions, such as the radiating aperture of a horn antenna or external metallic structures, CHAMP switches to a boundary element Method of Moments solver. By hybridizing Mode Matching with MoM, CHAMP avoids meshing the empty volume of the waveguide and the surrounding free space. It only computes surface currents on the metallic boundaries, which yields exact scattering parameters (S-parameters) and far-field radiation patterns with a fraction of the memory and processing power required by general-purpose volume-meshing solvers.
Key Mathematical Relations
Technical Specifications Comparison
| Simulation Parameter | Specialized Solvers (CHAMP) | Finite Element Method (HFSS) | Finite Integration Technique (CST) | |
|---|---|---|---|---|
| Primary Solver | Mode Matching + Method of Moments (MoM) | Finite Element Method (FEM) on 3D mesh | Finite Integration Technique (FIT) / FDTD | Domain decomposition / MoM |
| Mesh Dimension | 1D / 2D (Surface boundaries only) | 3D (Entire volume meshed) | 3D (Entire volume grid) | 3D (Volume or boundary) |
| Simulation Speed | Extremely Fast (seconds to minutes) | Moderate (minutes to hours) | Moderate (minutes to hours) | Slow-Moderate |
| Waveguide Optimization | Built-in analytical profile optimizer | Manual parameter sweeping | Manual parameter sweeping | Scripted sweep |
| Horn Antenna Analysis | Includes exact far-field radiation patterns | Requires large radiating boundary box | Requires PML boundary box | Requires hybrid boundary |
Frequently Asked Questions
What is the primary advantage of CHAMP over general-purpose 3D EM solvers?
The primary advantage is computational speed and efficiency. By using a hybrid Mode Matching and Method of Moments approach, CHAMP only meshes the surface boundaries of waveguide components rather than the entire 3D volume. This allows it to optimize complex corrugated horns and feed chains in seconds, compared to hours in general-purpose volume-meshing solvers.
What solver technologies does CHAMP employ?
CHAMP combines Mode Matching (MM) for internal, coaxial, or rectangular waveguide discontinuities and the boundary-element Method of Moments (MoM) for open-boundary radiating structures like antenna apertures. This hybrid approach ensures both analytical speed inside the waveguide and full-wave accuracy outside.
Can CHAMP model radiation patterns of horns?
Yes, CHAMP simulates both the internal S-parameters (reflection and transmission) of the feed chain and the external far-field radiation patterns. It computes copolar and cross-polar radiation patterns, phase center locations, and aperture efficiencies, which can be exported directly for reflector antenna analysis.