The Best RF Simulation Tool: HFSS vs The Rest
Electromagnetic simulation tools, like Ansys HFSS, vastly reduce errors and bottlenecks in RF design. However, each EM tool brings different features and advantages to engineering teams, such as advanced meshing, virtual prototyping, and compliance measures. In this article, we compare the features included in an HFSS license with the capabilities of other RF simulation tools.
What Is Electromagnetic Simulation?
Engineers use electromagnetic simulation to build and test virtual models of antennas, circuits, filters, and other electronic components in their products. These tools test the design against compliance regulations, real world conditions, and environmental interference. For example, a company building a patch antenna would first simulate it in a tool like HFSS to make sure their calculations are correct and that factors like signal integrity are within normal parameters.
Electromagnetic Simulation Tool Features
Most electromagnetic simulation tools complete the same tasks with roughly the same outcome, albeit with different user interfaces. However, each tool differs in the following cornerstone areas that affect your team's productivity and budget.
- Accuracy: Does the tool produce the correct results without additional input?
- Efficiency: How many iterations does it take to validate a simulation result?
- Computing Time: How long does it take to run a single model?
- Cost: What is the upfront price of the license, and how much does the tool save me in computing time costs and engineering costs?
- Compatibility: What software does this tool integrate with across our workflow?
Accuracy: HFSS vs The Rest
HFSS establishes its advantage through automatic adaptive meshing, which consistently converges to a numerically accurate solution without relying on user intuition or manual tuning. The 10-step simulation adapts the mesh to both geometry and localized electromagnetic behavior, producing finer resolution where it matters - gaps, vias, curved surfaces, and multiscale structures - while maintaining a stable, repeatable mesh across design variants. Therefore, adaptive meshing allows engineering teams to only run one simulation per component to achieve an accurate, verified result.
Competitors depend heavily on user-driven mesh refinement, which ties result accuracy to the engineer’s experience with EM behavior and meshing strategy. These accuracy limitations appear through staircasing of curved geometry, dispersion errors in time-domain numerical techniques, and mesh resolution that can miss sub-wavelength features. Therefore, competing users must run three separate simulations with different meshes - course, medium, and fine - to obtain verified results. Of these three simulations, two results must agree with each other with a 5% margin for error before it can be verified.
Efficiency: HFSS vs The Rest
Since HFSS only requires one simulation for verified results, users drastically cut down on compute time and engineering hours. The 10 step simulation takes 2 hours to run, then engineers can check the results and move to the next stage of the design cycle. This drastically reduces workflow bottlenecks, enabling teams to meet deadlines and get products to market more quickly.
Because competitors require multiple independent mesh studies to verify numerical accuracy, users spend more engineering hours validating results and still encounter inconsistencies between users. Each meshing stage varies in time required, ranging from 30 minutes to 6 hours. In total, users can expect approximately 9 hours of simulation time per result, leading to potential tight margins for error in meeting deadlines.
Cost: HFSS vs The Rest
Though upfront licensing costs vary, Ansys HFSS tends to sit at a premium point compared to the competition. However, HFSS requires fewer simulations, fewer mesh studies, and significantly less engineering time to reach validated accuracy. In total, HFSS costs only one-third of the engineering and computing expenses in a typical workflow. When extended across full development cycles, HFSS enables teams to deliver products weeks earlier, avoiding costly delays and protecting revenue.
What Tools are Compatible with Ansys HFSS?
HFSS integrates seamlessly across the Ansys ecosystem, enabling teams to combine electromagnetic simulation with thermal, structural, and multiphysics workflows. This compatibility streamlines complex system-level designs and supports organizations that require cross-domain verification. Adaptive meshing also behaves consistently for every user, making HFSS easier to integrate into larger teams and reducing onboarding effort.
Case Study: Simulating 50 Components with Ansys HFSS vs Competitors
To best compare Ansys HFSS with the rest of the field, let's test its performance against the top competitor under the same conditions. In this scenario, two teams of engineers are building a device that requires 50 unique components - antennas, filters, circuits, and so forth. Each component requires an accurate virtual model before the team can build the physical prototype. Both teams have a 90-day window to complete the project with a $27,700 impact if the project is early or late.
As these companies race to get to market, they've been tasked with keeping costs down as much as possible. Beyond the cost of the licenses for either HFSS or the competitor, the engineering cost is $85 per hour and computing cost is $0.50 per hour. Each simulation requires 0.5 hours of engineering time. Team 1 has an Ansys HFSS license, while Team 2 uses the top competitor's license.
1. Comparing Simulation Accuracy
As previously stated, HFSS's adaptive meshing feature allows engineers to get verified results after the first simulation. As a result, the engineers on Team 1 only need to run one simulation per component, leading to 50 total simulations. These results can immediately be transferred to the next stage of the design process.
However, Team 2 must perform three separate simulations per component to obtain verified results. After performing simulations with a coarse, medium, and fine mesh, two of the three results must agree with each other with a 5% margin for error. Assuming this is true for each component and no new calculations are needed, Team 2 must run 150 simulations total before moving it to the next stage of the design process.
2. Comparing Simulation Timeline
With only a 90-day window to complete the project, simulation time is critical to meeting the deadline as it briefly pauses the project. To run 10 adaptive step simulation, Ansys HFSS requires two hours of simulation time per component. This results in 100 hours of compute time and 25 engineering hours to simulate all components.
Using the top competitor, Team 2 must run each stage of meshing to obtain verified results. The course mesh takes 0.5 hours of simulation time, the medium mesh takes 2 hours of simulation time, and the fine mesh takes 6 hours of simulation time. All 50 components must run through each mesh once, leading to 450 hours of compute time and 75 engineering hours to simulate all components.
3. Comparing Cost per Design Cycle
Based on the figures calculated above, the compute cost per design cycle for Team 1 is $50 ($0.50 per hour, 100 hours). The engineering cost per design cycle is $2,125 ($85 per hour, 25 hours). This leads to a total cost of $2,175 using HFSS.
With the additional meshing and time required, Team 2 has a significantly higher compute and engineering cost. The compute cost per design cycle is $225 ($0.50 per hour, 450 hours). The engineering cost per design cycle is $6,600 ($85 per hour, 75 hours). Therefore, Team 2's total design cycle cost is $6,600.
4. The Results
To produce the exact same results, Team 1 saved 350 hours of compute time, 50 hours of engineering time, and a total of $4,425 by using Ansys HFSS.
Despite the many electromagnetic simulation tools on the market, Ansys HFSS emerges as the clear winner for accurate, cost effective results. Its adaptive meshing feature allows engineers to run fewer simulations to obtain accurate results, reducing the compute and engineering time required in your design cycle. This time-saving software allows companies to keep design costs lower and faster time to market than the competition, leading to higher potential revenue. When compared against the rest of the field, Ansys HFSS is the best simulation tool for RF design.
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