ANSYS HFSS Capabilities
High-Frequency Electromagnetic Solvers
ANSYS HFSS uses the highly accurate finite element method (FEM), the large-scale method of moments (MoM) technique and the ultra-large-scale asymptotic method of shooting and bouncing rays (SBR) with advanced diffraction and creeping wave physics for enhanced accuracy (SBR+). The ANSYS HFSS simulation suite has the following solvers to tackle manifold EM problems involving electrically small to enormous structures:
- Frequency Domain
- Time Domain
- Integral Equations
- Hybrid Technologies
- Shooting and Bouncing Ray
- Physical Optics
- Physical Theory of Diffraction
- Uniform Theory of Diffraction
- Creeping Wave
HFSS contains multiple simulation engines in one package, each targeted toward a specific application or simulation output.
HFSS Hybrid Technologies
The FEM-IE hybrid technology is built upon HFSS FEM, IE MoM and the patented ANSYS domain decomposition method (DDM) to solve electrically large and complex systems. By applying the appropriate solver technology, local regions of high geometric detail and complex materials are addressed with finite element HFSS, while regions of large objects or installed platforms are addressed with 3D MoM HFSS-IE. The solution is delivered in a single setup through a single, scalable and fully coupled system matrix.
Finite Element Method (Frequency Domain)
This is the high-performance 3D, full-wave, frequency domain electromagnetic solver based on the proven finite element method. Engineers can calculate SYZ parameters and resonant frequency; visualize electromagnetic fields; and generate component models to evaluate signal quality, transmission path loss, impedance mismatch, parasitic coupling and far-field radiation. Typical applications include antennas/mobile communications, integrated circuits, high-speed digital and RF interconnects, waveguides, connectors, filters, EMI/EMC, etc.
Finite Element Transient (Time Domain)
The Finite Element Time Domain solver is used to simulate transient EM field behavior and visualize fields and system responses in typical applications like time domain reflectometry (TDR), lightning strikes, pulsed ground-penetrating radar (GPR), electrostatic discharge (ESD) and electromagnetic interference (EMI). It leverages the same finite element meshing approach as the frequency domain solver, without the need to switch meshing technologies to switch simulation domains. The transient solver complements the frequency domain HFSS solver, and enables engineers to understand the EM characteristics on the same mesh in both time and frequency domains.
The integral equations (IE) solver employs the 3D Method of Moments (MoM) technique for efficiently solving open radiation and scattering problems. It is ideal for radiation studies like antenna design and/or antenna placement, and for scattering studies such as radar cross section (RCS). The solver can employ either multilevel fast multipole methods (MLFMM) or adaptive cross-approximation (ACA) to reduce memory requirements and solve times, allowing this tool to be applied to very large problems.
HFSS Fast Mode
For the early part of a product’s design cycle — where rapid simulation results can provide invaluable insight regarding design trends — HFSS includes a fast simulation mode. The fast mode tunes the solver and adaptive mesher to return results as fast as possible, without significantly compromising solution accuracy. Then, as the design nears completion, a simple slider bar setting sets the HFSS solver to return validation-level signoff accuracy using the industry tested, gold-standard accuracy capability of HFSS.
ANSYS HFSS SBR+
SBR+ is the only commercial electromagnetic solver to empower Shooting & Bouncing Ray (SBR) technology with simultaneous and consistent implementations of Physical Theory of Diffraction (PTD), Uniform Theory of Diffraction (UTD), and Creeping Wave for simulating installed antenna performance on electrically large platforms that are hundreds or thousands of wavelengths in size.
SBR uses a ray tracing technique to model induced surface currents on the antenna platform or scattering geometry composed of conductors and dielectrics. With the SBR+ solver, engineers can obtain fast and accurate prediction of far field installed antenna radiation patterns, near-field distributions and antenna-to-antenna coupling (S-parameters) on electrically medium, large and enormous platforms. Transmissions and reflections can be modeled in large structures like vehicles, aircraft, radomes, etc. HFSS SBR+ also provides efficient radar signature modeling, including ISAR images of electrically large targets.
Physical Theory of Diffraction
The Physical Theory of Diffraction (PTD) wedge correction feature is used for correcting PO currents along sharp edges of installed antenna platforms to refine EM field diffraction.
Uniform Theory of Diffraction
Engineers can model Uniform Theory of Diffraction (UTD) edge diffraction rays created by illuminated geometry edges and identified by PTD wedges. This is important for cases where the significant parts of the scattering geometry are otherwise shadowed from direct or multi-bounce illumination.
Creeping Wave Physics
Creeping Wave physics in the SBR solution improves the accuracy for antennas mounted directly on curved structures. It captures the effects of surface waves that are beyond the field source illumination horizon.
Accelerated Doppler Processing
Accelerated Doppler processing (ADP) accelerates simulation of long-, medium- and short-range pulse-Doppler and chirp-sequence frequency-modulated continuous-wave (FMCW) radars used in ADAS, autonomous vehicles and other near-field radar systems by more than 100x. ADP includes integrated range-Doppler image map post-processing and animation in the ANSYS Electronics Desktop. In addition to ADP, a gain and self-coupling antenna link streamlines the complete radar design process, so radar sensor simulation results can be used seamlessly in installed performance modeling and in radar-environment range-Doppler simulations. The workflow simplifies the collaboration between radar sensor designers and the OEMs that incorporate the sensors on vehicles and in large-environment radar simulations.
Reliability and Automatic Adaptive Meshing
Engineers know and rely on ANSYS HFSS to provide accurate solutions automatically. The key to this reliability is automatic adaptive mesh refinement, which generates an accurate solution based on the physics and electromagnetics of the design. This contrasts with other electromagnetics (EM) simulation tools where the engineer is expected to know how to mesh the structure to get an accurate solution. Automatic adaptive meshing is a highly robust meshing technique that produces an efficient mesh for guaranteed accuracy as quickly as possible. You need only import or draw the geometry, and specify materials, boundary conditions, excitations and the frequency band of interest, and HFSS takes care of the rest.
To minimize the need for “healing and cleaning” of imported CAD geometry, powerful TAU flex meshing technology is included within HFSS. TAU flex quickly produces a reliable initial mesh from the “dirtiest” of models, so you can quickly advance through the solution process with the accurate and reliable solver technology of HFSS.
Optimized User Environment
The full-featured 3D solid modeler and layout interface enables you to work in a layout design flow, or to import and edit 3D CAD geometry.
HFSS 3D Modeler: The 3D interface enables you to model complex 3D geometry or import CAD geometry for simulation of high-frequency components, such as antennas, RF/microwave components and biomedical devices. You can extract scattering matrix parameters (S, Y, Z parameters), visualize 3D electromagnetic fields (near- and far-field) and generate ANSYS Full-Wave SPICE models that link to circuit simulations.
HFSS 3D Layout: HFSS 3D Layout is an optimized interface for layered geometry of PCBs, IC packages and on-chip passives. It is suitable for analyzing the signal integrity of PCBs and packages, including full-wave or radiative effects. Applications range from high-speed serial links with complex breakout regions and poorly referenced transmission lines, to patch antennas and millimeter-wave circuits. Engineers can draw or import geometry to analyze electromagnetic behavior, display radiated fields, investigate impedances and propagation constants, explore S-parameters or calculate insertion and return loss.
The model is assembled and rendered in a Layout environment; however, all effects are rigorously simulated, including 3D features such as trace thickness and etching, bond-wires, and solder balls. Layout geometry is primarily described in 2.5D with a stack-up and specialized primitives such as vias, pins, traces and bond-wires. The editor is completely parametric, so trace widths or thicknesses can be easily varied or parameterized for sweeps, optimization or design-of-experiments (DOE). The HFSS solver within 3D Layout includes many features targeted specifically for PCB and package structures. These features include advanced meshing technology optimized for layered geometry and integrated circuit elements and S-parameters for modeling of discrete components.
To accurately predict a system’s performance, analyzing the electronic interaction between components and subsystems in an integrated environment can be critical. HFSS 3D Layout allows for creation of a PCB assembly, connecting boards, ICs and discrete components. With this approach, you can pick and place 3D connector models on a PCB without the need to create a schematic. Electrical engineers have long used schematic-based design entry to connect models together for printed circuit boards, IC packages and components. This works well for relatively simple designs, but becomes tedious and error prone for larger and more complex designs. With layout-driven assembly, pin connections are automatically established based on the geometry. Once an assembly is created, HFSS 3D Layout can invoke a range of solvers appropriate for each component, or geometries can be merged and solved together.
From the HFSS 3D Layout interface, you can access an expanding list of solvers, which include HFSS, SIwave and Planar EM. This allows for iterative design using fast SIwave solves, and rigorous verification using HFSS, all from the same design and geometry.
ANSYS 3D Components represent discrete subcomponents of a larger simulation that can be easily re-used for electromagnetic simulations in ANSYS HFSS. 3D Components can encapsulate geometry, material properties, boundary conditions, mesh settings, excitations and discrete parametric controls. They are convenient for design re-use for devices such as antennas, connectors and surface mount devices like chip capacitors, inductors and discrete LTCC filters. To enable industry-wide collaboration, ANSYS 3D Components can be created with password protection, file encryption and creation settings to discreetly control which features are visible to a component end-user. However, the HFSS simulation engine is fully aware of the entire component within the simulation, and therefore provides a fully coupled and complete electromagnetic simulation result.
An ANSYS 3D Component can be likened to a building block of a simulation implemented as a plug-and-play module. Since 3D Components provide a fully coupled electromagnetic analysis, they have a distinct advantage over an S-parameter model which only delivers a response of a component on its test fixture. A system integrator just adds the component onto a system such as a 3D Component of an antenna on an aircraft to simulate the installed performance of the antenna. They can do this with the confidence that the simulation results represent a fully coupled and accurate model simulated with ANSYS HFSS.
Vendors and developers of discrete components can create simulation-ready 3D Components in ANSYS HFSS and provide them to end-users who can reference them in larger system simulation. With this ability to collaborate through 3D Components, vendors can provide their customers with HFSS simulation-ready models, giving them a valuable edge in enabling first-pass design success.
Modelithics®, an ANSYS partner, offers a licensed library of HFSS 3D components. The library includes models for the Barry QFN package, RJR QFN package, Coilcraft inductors, Johanson capacitor, Mini-Circuits filter and Gigalane coax connector. More information can be found on the Modelithics website at www.Modelithics.com/model/models3D.
Advanced Phased Array Antenna Simulation
In ANSYS HFSS, engineers can simulate infinite and finite phased-array antennas with all electromagnetic effects, including mutual coupling, array lattice definition, finite array edge effects, dummy elements, element blanking and more, through advanced unit cell simulation. A candidate array design can examine input impedances of all elements under any beam scan condition. Phased array antennas can be optimized for performance at the element, subarray or complete array level based on element match (passive or driven) far-field and near-field pattern behavior over any scan condition of interest.
Infinite array modeling involves one or more antenna elements placed within a unit cell. The cell contains periodic boundary conditions on the surrounding walls to mirror fields, creating an infinite number of elements. Element scan impedance and embedded element radiation patterns can be computed, including all mutual coupling effects. The method is especially useful for predicting array-blind scan angles that can occur under certain array beam steering conditions.
Finite array simulation technology leverages domain decomposition with the unit cell to obtain a fast solution for large finite-sized arrays. This technology makes it possible to perform complete array analysis to predict all mutual coupling, scan impedance, element patterns, array patterns and array edge effects.
ANSYS Electronics HPC enables parallel processing for solving the toughest and most challenging models — models with great geometric detail, large systems and complex physics. ANSYS goes well beyond simple hardware acceleration to deliver groundbreaking numerical solvers and HPC methodologies optimized for multicore machines, with scalability to take advantage of full compute cluster power. The amount of HPC required is based simply on the total number of cores used in the analysis, irrespective of which HPC technology is employed.
Multithreading: ANSYS Electronics HPC takes advantage of multiple cores on a single computer to reduce solution time. Multithreading technology speeds up the initial mesh generation, matrix solves and field recovery.
Spectral Decomposition Method: The spectral decomposition method (SDM) accelerates frequency sweeps by distributing multiple frequency points in parallel over compute cores and nodes. You can use this method in tandem with multithreading to speed up extraction of individual frequency points, while SDM parallelizes multi-frequency point extraction.
Domain Decomposition Method: The domain decomposition method (DDM) accelerates the solution for larger and more complex geometries by distributing a simulation across multiple cores and networked nodes. This method is primarily designed to tackle larger problem size using distributed memory. It can also be combined with multithreading and SDM to provide improvements in simulation scalability and throughput.
Periodic Domain Decomposition: Periodic domain decomposition applies DDM to finite periodic structures such as antenna arrays or frequency selective surfaces. This method virtually duplicates the geometry and mesh of the periodic structure’s unit cell and then applies the DDM algorithm to the resulting finite sized array to solve for the unique fields for all elements. Simulation capacity and speed are substantially increased. This method can be combined with multithreading and SDM to further accelerate the solution.
Hybrid Domain Decomposition Method: Hybrid DDM uses the domain decomposition method on models consisting of finite element (FE) and integral equation (IE) domains. The HFSS IE solver add-on lets you create HFSS models that can solve extremely large EM problems. This methodology combines the virtues of FEM’s ability to handle complex geometries plus MoM’s efficient solutions for antenna and radar cross section analysis. Hybrid DDM can be combined with multithreading and SDM to provide further solution acceleration.
Distributed Direct Matrix Solver: The distributed direct matrix solver is a distributed memory parallel technique for HFSS and the HFSS-IE solvers. The matrix solution is distributed across multiple cores or MPI-integrated computers. It results in solutions with improved scalability through increased MPI memory access, and enhanced speed through increased MPI networked core access for highly accurate direct matrix solver solutions. These distributed memory matrix solvers can be combined with multithreading and SDM to further increase simulation throughput.
HPC in the Cloud: The ANSYS Cloud service makes high-performance computing (HPC) extremely easy to access and use. It was developed in collaboration with Microsoft Azure, a leading cloud platform for HPC. It has been integrated into the Electronics Desktop, so you can access unlimited, on-demand compute power from the design environment. For more information visit the ANSYS Cloud page.
RF OptionThe ANSYS RF Option combined with HFSS creates an end-to-end high-performance RF simulation flow. It includes ANSYS EMIT, a unique multi-fidelity approach for predicting RF system performance in complex RF environments with multiple sources of interference, and provides the diagnostic tools needed to quickly identify root-cause RFI issues. The RF Option also includes ANSYS Circuits, which includes a harmonic balance circuit simulation, 2.5D planar method of moments solver, filter synthesis and more.
RF Option Features
- RF link budget analysis
- Built-in wireless propagation models
- RF co-site and antenna coexistence analysis
- Automated diagnostics for rapid root-cause analysis
- Quick assessment and comparison of potential mitigation measures
- RF radio and component libraries
- Multi-fidelity behavioral radio models
- Antenna-to-antenna coupling models
- DC analysis with multiple continuation options
- Multitone harmonic balance analysis
- Oscillator analysis
Autonomous Plus Driven Sources Option
- Time varying noise and phase noise analyses
- Envelope analyses
Multicarrier Modulation Support
- Load pull analysis and model support
- Periodic transfer function analysis
- Transient analysis
HFSS combined with the ANSYS SI option is ideal for analyzing signal integrity, power integrity and EMI issues caused by shrinking timing and noise margins in PCBs, electronic packages, connectors and other complex electronic interconnects. HFSS with the SI option can handle the complexity of modern interconnect design from die-to-die across ICs, packages, connectors and PCBs. By leveraging the HFSS advanced electromagnetic field simulation capability dynamically linked to powerful circuit and system simulation, engineers can understand the performance of high-speed electronic products long before building a prototype in hardware. This approach enables electronics companies to achieve a competitive advantage with faster time to market, reduced costs and improved system performance. The ANSYS SI option adds transient circuit analysis to HFSS. This enables engineers to create high-speed channel designs that include the driving circuitry as well as the channel. The driving circuitry can be transistor level, IBIS-based or ideal sources. When performing an analysis on these channels, you can select from a variety of analysis types:
- Linear network analysis (included with HFSS)
- Transient analysis
- QuickEye and VerifEye analyses for fast eye generation in high-speed channel design, bathtub curves, jitter and eye masks
- Monte Carlo analysis supporting Spectre® and HSPICE® functionality
- DC analysis with automated convergence
- Dynamic links with ANSYS Q3D Extractor and ANSYS SIwave
- IBIS-AMI analysis and model support
Multidomain System Modeling
ANSYS Simplorer is a powerful platform for modeling and simulating system-level digital prototypes integrated with ANSYS Maxwell, ANSYS HFSS, ANSYS SIwave and ANSYS Q3D Extractor. Engineers can verify and optimize performance of their software-controlled, multidomain systems. With flexible modeling capabilities and tight integration to ANSYS 3D physics simulation, Simplorer provides broad support for assembling and simulating system-level physical models to help engineers connect conceptual design, detailed analysis and system verification. Simplorer is ideal for electrified system design; power generation; conversion; storage and distribution applications; EMI/EMC studies and general multidomain system optimization and verification.
- Circuit simulation
- Block diagram simulation
- State machine simulation
- VHDL-AMS simulation
- Integrated graphical modeling environment
- Analog and power electronics components
- Control blocks and sensors
- Mechanical components
- Hydraulic components
- Digital and logic blocks
- Aerospace electrical networks
- Electric vehicles
- Power systems
- Characterized manufacturers components
- Reduced order modeling
- Power electronic device and module characterization
- Co-Simulation with MathWorks Simulink
This capability provides automatic and customizable EMI design rule check of PCBs. EMI Scanner can quickly identify areas of potential interference on your PCB design prior to simulation. EMI issues traditionally have been difficult to simulate and require hours of computational time. This new feature included within ANSYS SIwave and ANSYS HFSS quickly identifies potential trouble spots that require further investigation. It eliminates errors and speeds time to market.