r/rfelectronics • u/isomoki • 2d ago
I’m building Fairbeam, a free and open-source antenna simulation app
Hey everyone! I’ve been working on Fairbeam, a free and open-source app for designing and simulating antennas, and thought some of you might enjoy trying it.
It brings 3D modeling, meshing, simulation, and plots into one workspace, using openEMS, CSXCAD, and three.js. You can draw a model visually or use Python, then inspect S-parameters and radiation patterns.
It’s available for macOS and Windows, with experimental Linux support. Optional GPU acceleration uses CUDA on NVIDIA GPUs and Metal on Apple silicon.
It’s still early, so I’d love to hear what feels useful, what’s confusing, and what breaks. The code is GPL-3.0-or-later. Feel free to dig in, change things, or contribute an example!
Website: https://fairbeam.org
Code: https://github.com/ismailakdag/fairbeam
As with any simulation tool, please check the results against a reference you trust.
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u/1LimePlease 2d ago edited 2d ago
Just like this one? [1]
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u/isomoki 2d ago
Thanks for sharing! Fairbeam currently uses FDTD, with FEM integration planned too. My main focus is keeping the whole project free and open source, including CUDA and Metal GPU support. There’s no paid tier or features behind a paywall. It’s built on open-source solvers, and I’d like to build it together with the community so anyone can contribute and help shape where it goes.
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u/1LimePlease 2d ago
That’s cool. But I suggest combining your efforts with an already developed project, that would contribute more to the community than making half-baked calculators 😋
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u/isomoki 2d ago
Sorry, I’m not sure I follow. Is the project you shared open source? If so, I’d be happy to contribute. I use these tools almost every day and started Fairbeam to build a workflow I’d enjoy using myself. Have you tried it? I’d genuinely like to improve whatever feels “half-baked” to you. A few specifics would help me finish baking it 😋
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u/1LimePlease 2d ago
I mean the principle. I’ve seen a lot of attempts to create solvers in this sub, but in terms of quality, can they really perform anywhere close to professional tools like CST?
It would really suck to spend months hunting down RF bugs with software I’m not familiar with, only to find out later that the problem was actually a software bug.
Your intentions are good, but I’m highly skeptical that a single developer could match software quality of an entire development team behind a professional tool.
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u/isomoki 2d ago
Of course, I agree with you on this and respect your point. But my goal isn’t to build something better than CST. CST’s licensing costs are well known, and you probably know that students or researchers can struggle to simulate even relatively small structures with the educational version.
I used AI under my direction to build a program I’d feel comfortable using myself. It uses openEMS, an open-source solver known in the literature, and brings the simulation and results-viewing process together in a more user-friendly environment. I didn’t write the solver, and the graphics engine isn’t mine either. But integrating these parts was done under my supervision, and at each stage I tried to compare things with both open-source tools and commercial software I could access.
As you may have noticed, I have no financial expectations from this. I enjoy doing it. I’m an RF and microwave engineer myself, and I find it exciting that AI can help create things like this. As I mentioned earlier, I want to build something with the community and meet others working in this field. As you know, it isn’t a particularly large community.
But of course, I agree with what you’re saying. I couldn’t do something on that scale entirely on my own. I’m mainly developing something for myself and for others who could use it as an open-source tool.
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u/jephthai 21h ago
When the pro solvers cost as much as a car, there's a lot of room for open source solutions. For those of us who don't have an employer to pay for these things, it's slim pickings. The item source tools actually work great, and just need a usability veneer to take off.
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u/StageMajestic613 1d ago
I’ll let you in on a secret. The Big Gorilla CAD tools don’t have a lab where they are refining their tools with measured vs. modeled. No EM tools are developed like that. They do have automated regression testing where they’ll sim a bunch of analytic or well known standards, and they also have bugs. One popular solver was written by ONE guy. The office didn’t have a lab, but it did have a kegerator.
It’s up to you as an EE to known when stuff looks strange, or how you’d expect your circuit to work. You don’t blindly plug it in a trust an answer. You do things like mesh refinement and look for convergence, plot currents and see where they are supposed to be.
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u/Key-Indication3921 2d ago
every project gets completed over time being half baked right now doesnt mean it will always stay that way, by your logic developing anything other than CST and HFSS is also half baked in my opinion? i suggest developers get jobs at companies like SIMULIA and stop working on "half-baked" projects ^^
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u/jephthai 21h ago
Wow, you're getting down votes? Tough crowd. You're absolutely right. The professional tools are inaccessible to the hobbyist world, so any movement in the open source side is good.
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u/RoyBellingan 2d ago
As with any simulation tool, please check the results against a reference you trust.
And that is why I am inclined to trust it.
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u/isomoki 2d ago
I get your point, and it’s a fair concern. I used openEMS as the backend, which you can look into too. Numerical EM methods produce approximate solutions; FDTD discretizes Maxwell’s equations in space and time. Depending on the problem, FDTD, FEM or MoM may be more suitable. I’ve tested around 40 designs, but convergence checks and independent validation still matter. It would be misleading for me to claim that it solves every problem accurately.
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u/jephthai 19h ago
Very nice -- I saw you posted this somewhere else the other day. I'm also working on a modeling suite for antenna simulation, but with a very different modeling paradigm. Yours is very CAD-like, and I like how you've designed it. Mine is more procedural / DSL-based, so they're just different.
I did actually look at a few of your implementation details to see how you've handled some challenges I've run into.
Thanks for posting it. IMO, usable and cheap (especially free) tooling is one of the biggest barriers to enthusiasts getting into RF at the hobby level. I've scrabbled and clawed for years to get any kind of simulation regime to work for my projects, and always been frustrated at the elitist attitudes you get from people whose employers pay for HFSS, etc. :-/.
There is a burst of LLM-assisted activity in basically just making usable interfaces to the clunky and almost antagonistic simulation tools that exist in the open source space (OpenEMS, MEEP, Palace, etc.). It's a great fit -- we're not asking AI to do the hard part; that's already done on the back end. We need repeatable and usable instrumentation to use it.
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u/StageMajestic613 1d ago
Looks very cool. I’ll have to give it a try. I see the toolbar is very CST, so hopefully similar functionality. Yes, if you can get FEM in there that would be killer as FDTD isn’t great for high Q stuff.
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u/isomoki 1d ago
Thanks! Yeah I took some inspiration from CST 😅 since I've been using it for years and comfortable with its workflow. I'm trying to integrate ElmerFEM to same workflow.
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u/StageMajestic613 1d ago
I’d actually have the AI write your own solvers, that way you have complete control of them and they are more tightly integrated.
A big pain point with all tools is 2D vs 3D editing. If you can create an editor that has a 2D mode for fast polygon pushing (i.e. dragging edges and nodes, slicing, stretching) in addition to the kernelish based 3D editing, you’ll have a killer program. Ansys has attempted to solve this (I have not used it) with their 2D editor, but it’s not in the HFSS GUI. None off them will as they are based on the ACIS kernel.
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u/Mechanical_Flare 1d ago
Please disclose AI usage.
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u/isomoki 1d ago
Do you want me to add details on the post? You can find information about AI here: https://github.com/ismailakdag/fairbeam/blob/main/AI_POLICY.md#how-fairbeam-is-made
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u/StylentIV 2d ago
I am on this website since 2010 and this is the best project i have ever seen. nice one
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u/pauling_was_a_nut 2d ago
What the hell is going on? There's been a half dozen vibe coded RF design tools getting shilled on this sub within the last month.