FDTD-Simulators.md

Background

List of Electro-Magnetic (EM) that impliment the Finite Difference Time Domain algorithm. I specifically am choosing a simulator for optimizing a Time Domain Reflectometer (TDR) for level measurements and profiling applications. I prefer open source solutions for transparency, customization, and integration into automation workflows.

• Open-Source Software for Electromagnetic Scattering Simulation
• GDSFactory has a good discussion of some options
• Wikipedia Has an incomplete list.

FOSS FDTD Simulators

OpenEMS

• Website
• Repo
• Docs
• License: GPLv3
• Forum (it's active)
• Uses: RF Electronics, PCB Simulations, General Use
• Scripting: Octave/Matlab, Python, and C++ API
• Resources
  • FOSDEM Slides 2019
  • gerber2ems: Gerbers to OpenEMS tools. Interesting articles from them here and here.

Meep

• Repo
• Docs
• License: GPLv2
• Forum
• Scripting: Scheme, Python, and C++ API
• Target Use: Photonics
• Resources
  • Introduction to MEEP (2005)

GPRMax

• Website
• Repo
• Docs
• License: GPLv3
• Forum
• Target Use: Ground penetrating radar
• https://arxiv.org/pdf/2106.13737

FDTDX

• Repo
• Docs
• License: MIT
• Scripting: Python
• Target Use: Photonics
• https://arxiv.org/html/2412.12360v1#bib.bib25

Aether

• Website
• Repo
• License: Apache 2.0
• Forum
• Target Use: Photonics

FDTD++

• Website
• Download
• License: AIML claims to be GPL-like but no, no it is not.
• Forum: Seems to be broken

Flaport FDTD

• Repo
• Docs
• License: MIT
• Forum: None
• Scripting: Python
• Target Use: Photonics

Rose Engineering RFDTD

• Repo
• License: None Listed
• Forum: None
• Scripting: Python
• Target Use: RF Electronics

FDTD3D

• Repo
• License: GPLv2
• Forum: None
• Scripting: C++ API
• Fairly limited feature set.

FanCompute Ceviche

• Repo
• License: MIT
• Forum: None
• Scripting: Python
• Mostly an FDFD solver. The FDTD is very limited.

Cool FDTD Projects

pffdtd

• Repo
• License: MIT
• Forum: None
• Scripting: Python
• Target Uses: Room acoustics for rooms modeled using sketchup.

Commercial

Empire XPU

• Website
• Target Use: RF, ID Design, PCBs, General Use

Ansys Lumerical

• Website
• Target Use: Photonics

Ansys HFSS

• Website
• Target Use: RF, General Use
• Ansys has student licenses here and is commonly used for undergrad antenna design courses.

Flexcompute Tidy3D

• Repo
• Website
• License: Proprietary
• Cloud based simulation, billed by use time on their servers.

Simworks

• Website
• Cloud based simulation, billed by use time on their servers.

Synopsys Fullwave

• Website
• Target Use: Photonics

Remcom

• Website

Conclusion

For what I'm trying to do (TDR optimization) the most powerful opensource option is openEMS although Meep and GPRMax are close contenders I'd like to explore. HFSS and EmpireXPU are well regarded tools which are worth exploring.