openEMS — The Complete Guide: Free FDTD Electromagnetic Simulation for Antennas and RF
openEMS is an open-source electromagnetic field solver (GPL-3.0) based on the finite-difference time-domain (FDTD) method. You define geometry, materials and excitation in an Octave, MATLAB or Python script and get the electromagnetic response of the structure.
openEMS
Thorsten Liebig and contributors
A 3D FDTD electromagnetic field solver — antennas, RF filters and PCB structures, scripted in Octave, MATLAB or Python.
Get it from the vendorWhat you get
- S-parameters — reflection and transmission of the structure across frequency.
- Input impedance — for matching antennas and feed circuits.
- Radiation patterns — of antennas in every direction.
- Field distributions — the field inside and around the structure.
- A wide range of uses — antennas, microwave filters, transmission lines and structures on printed circuit boards.
What to know
There is no full graphical interface for building the model — the work is done in code, and large models take considerable run time. Windows has ready binaries; on Linux it is built from source and on macOS installed through Homebrew. It is a strong free alternative to commercial solvers, for any use including commercial work.
Related tools
For FDTD simulation in photonics and optics — Meep. To run the scripts without a MATLAB licence — GNU Octave. To design the board itself — KiCad.
Meep
NanoComp / Meep developers
FDTD electromagnetic simulation for photonics — waveguides, resonators, photonic crystals and inverse design.
Get it from the vendor
GNU Octave
GNU Project
Numerical computing in MATLAB-compatible syntax — matrices, equations, signals and plots.
Get it from the vendor
KiCad
KiCad Development Team
Open-source PCB design suite, from schematic to fabrication files, with no limit on layers or board area.
Get it from the vendor
Qucs-S
Qucs-S Project
Circuit simulation with a graphical schematic front end over SPICE engines.
Get it from the vendorThe bottom line
openEMS is a serious, free electromagnetic solver — a good fit for RF engineers who are ready to build the model in code.