System-Level EMC Simulation Using SIwave, HFSS, and Ansys EMC Plus

Electromagnetic compatibility (EMC) challenges are becoming increasingly complex as modern electronics evolve into tightly integrated systems. Products across aerospace, automotive, and consumer electronics combine high-speed digital circuits, radio frequency (RF) components, dense printed circuit boards (PCBs), and extensive cable harnesses within compact enclosures. Accurately predicting EMC performance requires multi-domain analysis rather than isolated modeling.

“EMC is not a single component problem,” explains Synopsys Principal Product Manager Juliano Mologni. “It’s the integration of ICs (integrated circuits), PCBs, antennas, cables, and connectors.”

To address this complexity, Electro Magnetic Applications, Inc. (EMA) and Synopsys support workflows that connect PCB-level, 3D electromagnetic (EM), and system-level simulation. Ansys SIwave, HFSS, and EMC Plus link component-level modeling with system-level EMC analysis.

Why Integrated EMC Simulation Matters

EMC behavior is inherently a system-level phenomenon. Failures arise from interactions between PCBs, connectors, cables, antennas, and enclosures rather than a single isolated component.

Traditional approaches often remain domain-specific:

• PCB tools focus on signal and power integrity
• RF solvers analyze antennas and high-frequency structures
• System tools model enclosure-level behavior

While each provides value, they do not independently capture cross-domain coupling mechanisms.

“When it comes to EMC, you need to consider many different components and systems,” Mologni says.

An integrated workflow enables:

• Multi-domain EM analysis
• Field-level visibility across the entire system
• Early identification of failure mechanisms

Role of Each Solver in the Workflow

SIwave: Fast, Accurate PCB-Level Analysis

SIwave is optimized for layered structures such as PCBs and IC packages, avoiding volumetric meshing by modeling currents and fields within planar geometries.

Key capabilities include:

• Signal integrity and power integrity analysis
• DC voltage drop, current density, and thermal coupling evaluation
• S-parameter and RLC extraction

This approach reduces computational cost compared to full 3D methods, enabling rapid iteration during PCB design.

HFSS: High-Fidelity 3D Electromagnetic Modeling

HFSS uses the finite element method (FEM), which applies conformal meshing to accurately resolve complex geometries, material boundaries, and fine structural details. This makes it well-suited for RF and microwave components where geometric fidelity directly impacts results.

It excels at modeling:

• Antennas and RF components
• Microwave systems and high-frequency structures
• Advanced packaging and 3D interconnects

Encrypted 3D components allow accurate modeling while protecting proprietary geometry.

EMC Plus: System-Level EMC Simulation

EMC Plus uses finite-different time-domain (FDTD)-based techniques for large-scale system analysis, enabling efficient simulation of broadband and transient behavior across full product assemblies.

“Only EMC Plus can handle this level of real-world system complexity,” Mologni notes.

EMC Plus supports:

• Cable harness and transmission line modeling
• Enclosure and shielding analysis
• Radiated and conducted emissions
• Transient effects such as lightning strikes

By leveraging FDTD for field propagation with transmission line models for cables, EMC Plus captures system-level interactions without the computational cost of full 3D discretization.

How Integration Works

Step 1: PCB Radiation from SIwave

SIwave computes near-field radiation from the PCB across a specified frequency range. This data is exported as a field data set and imported into EMC Plus, where it acts as a radiating source within a larger system model. This eliminates the need to re-simulate the PCB in 3D and preserves accuracy while significantly reducing simulation time.

Mologni notes that this step completes in about five minutes compared to hours using full 3D solvers.

Step 2: Antenna Modeling from HFSS

HFSS generates equivalent radiation sources using Huygens surfaces, which capture the EM fields surrounding an antenna. These sources are then imported into EMC Plus, enabling realistic representation of antenna behavior in the system. Benefits include maintaining full-wave accuracy and avoiding duplicating computational cost.

The antenna process in HFSS takes about five minutes says Mologni.

Step 3: Assemble the Full System in EMC Plus

In EMC Plus, engineers combine:

• PCB radiation sources from SIwave
• Antenna models from HFSS
• Cables, enclosures, and environmental conditions

The result is a unified simulation environment that supports radiated emissions analysis, susceptibility testing, cable coupling and shielding evaluation. This approach enables true end-to-end EMC simulation, bridging previously isolated domains.

The entire workflow from setup to results takes about half a day, Mologni states.

Performance Advantage of the Integrated Workflow

One of the most significant benefits of this integrated approach is simulation efficiency. Typical performance improvements include:

• PCB near-field extraction in minutes instead of hours in SIwave
• Antenna simulation in HFSS completed within minutes for source generation
• Full system EMC simulations completed in hours rather than days in EMC Plus

Accuracy and Validation

Cross-domain workflows require validation to ensure accuracy is maintained during data transfer.  Simulation results show strong agreement with measured EMI/EMC data, including:

• Surface current distributions
• Radiation emissions
• Cable coupling behavior

“Simulation results are matching experimental results really well,” Mologni explains. “When you get this kind of correlation, you can really trust the results.”

Comparisons between HFSS and EMC Plus also show consistent field and waveform results for shared scenarios, supporting the validity of the integrated approach.

Real-World Applications

This integrated workflow is already being applied across industries, including:

• Aerospace: Lightning strike analysis and cable interactions
• Automotive: EMC validation for infotainment and control systems
• Consumer Electronics: Antenna interference and enclosure coupling
• Industrial Systems: Complex cable harness and shielding evaluations

These applications benefit from system-level modeling of realistic operating conditions.

Read the case study “Intel Achieves EMI Simulation of an Entire Server with Help from Ansys and EMA” for a closer look at how this method was used.

From Component Models to System Insight

As system complexity increases, EMC must be addressed throughout the design process rather than at validation.

Combining SIwave, HFSS, and EMC Plus enables:

• Multi-domain simulation across PCB, RF, and system levels
• Reduced simulation time through domain-specific solvers
• Improved prediction of EMC performance prior to testing

“You’re just one click away from full system EMC simulation,” Mologni says. “It’s extremely simple to get results.”

This approach transforms EMC simulation from a reactive process into a proactive design strategy, reducing risk, accelerating development, and enabling more robust products.

See this workflow in practice in the Solving Electromagnetic Challenges webinar “Integration of Ansys EMC Plus, SIwave, and HFSS.” Watch here.

Connect with EMA to:

• Learn more about how to use this integrated approach
• Review your PCB, system, or enclosure designs to identify potential EMI/EMC risks early
• Build a complete system-level simulation workflow tailored to your product and requirements
• Accelerate your path to compliance with guidance based on proven workflows and real-world validation

Show us your designs and get started with full system EMC simulation today. Contact us here.