Free EDA software

Free EDA software

Click here to go to our main page on computer-aided design

Note: We've updated the page as of February 2023, thanks to some good input from Carsten. As always, links are subject to change at the whim of the site owners! 

On this page we provide links to free EDA software.  Not all of it has been checked out by us, so buyer beware. 

Circuit board Milling software

New for February 2023: Gerber artwork can be imported into shareware called FlatCAM, which generates multiple output files for multiple tools.  Here's a video of circuit board milling that will familiarize you with the process.

RF measurement and data analysis software

SPLOTRF (new for August 2022)

This is a free S-parameter plotting tool.  Damon pointed this out to us in February 2022. Thanks! You can find it in the Apple store.  Here is his description of the product:

Key Features

• modern interface

• arbitrary number of ports (.s1p, .s2p, s3p…snp support)

• S/Y/Z matrix conversion

• mA/ri/dB formatting

• interpolation over frequency

• exports high quality vector graphics to .pdf

• plotting display properties and configuration are saved within file comments

• automated grid layout

• Smith Chart, Polar and Rectangular plots

• reads and plots .zip archives containing s-parameter data

The Good News

• free

• supports iPhone, iPad and Mac OS X

• available on the App Store

The Bad News

• not on Windows or Android (yet!)


METAS VNA Tools (new for February 2020)

Thanks to Juerg... VNA Tools is a free software developed by the National Metrology Institute from Switzerland (METAS) for measurements with the Vector Network Analyzer (VNA). The software facilitates the tasks of evaluating measurement uncertainty in compliance with the ISO-GUM and vindicating metrological traceability.

This VNA metrology application was originally developed for National Metrology Institutes and high-level industry laboratories but we do see now an increased interest from industry, accredited laboratories and academia. One of the reasons is to have access to a complete uncertainty budget and therefore being able to identify the main error sources (where to put the resources to increase the accuracy). The other reason is to compare the impact on accuracy by applying different calibration methods or calibration standard definitions on exactly the same S-parameter raw data.

In addition it saves a lot of time for any accredited lab for the measurements and the needed quality management documentations. Just to come up with your best measurement capability calculations (needed for the scope of accreditation) allows you to save weeks of work compared to use the existing techniques. Other new implemented features are time domain conversion, material characterization calculations (complex permittivity and permeability) and mixed mode S-parameter conversions – all with linear uncertainty propagation.
VNA Tools does support coaxial, waveguide and on-wafer S-parameter measurements. Even a virtual VNA is built in to create artificial measurements – this is very convenient for educational purposes as no VNA hardware is needed to demonstrate the S-parameter metrology and the impact from the different possible calibration methods.


From Simon: I’m using also widely WinCal for another purpose : viewer of S-parameter files. Wincal from Cascade can be freely downloaded. No restriction for using as a S-parameter file viewer.


The NIST site offers a variety of free software, including various on-wafer calibration software (MultCal, for TRL and LRM), transmission line calculators, uncertainty calculators etc.  It is well worth a few minutes of your time to see what they have.


For data review ParaView is a fantastic program it accepts all sorts of data files and  automatically will plot, animate etc.

EM solvers


This suggestion came from Phil:

If one needs EM 3D software, they should check out openEMS at  I've found this very useful and quite well-supported for free software. It does FDTD full 3D simulations and I use it for both optics and RF simulations.

According to the website, openEMS is a free and open electromagnetic field solver using the FDTD method. Matlab or Octave are used as an easy and flexible scripting interface.


Sonnet provides a free student version of their planar EM solver. Look for it here:

Characterization of Printed Transmission Lines at High Frequencies, Software Tool (MATLAB tool) 

This offering is somewhere between an EM solver and a linear simulator... it's free MatLab code that will help you calculate radiation loss, thanks to Sven van Berkel! It is based on a quasi-analytical approach and was written at TU Delft.  Check it out and tell us how it works for you. It is a stand-alone executable file so you don't need a MatLab license. All the libraries needed are included in the executable. Thanks!

Linear simulators


Developed by Dr. Alex Arsenovic from University of Virginia, scikit-rf (aka skrf) is an Open Source, BSD-licensed package for RF/Microwave engineering implemented in the Python programming language. It provides a modern, object-oriented library for network analysis and calibration which is both flexible and scalable. 

When baby-boomer microwave engineers retire we can rest easy knowing that smart, motivated, stick-shift-driving engineers like Alex will take up the slack.

Start here, then try some of the free downloads.

scikit-rf 800



Update February 2023.  The Z0lver site appears to be gone.  Anyone know what happened? Is it available elsewhere?

Z0lver is a cross-platform transmission line and circuit "z0lver" (solver) that links schematic capture, analysis and visualization, and fabrication of printed RF/microwave circuits.  This input came from Jeff in June 2015:

I'm one of the founders of Raven Standard LLC. We are a group of emag enthusiasts that have spent the last bit (1.5 years) of time developing a free, open-source emag app. I am now happy to say that this is free for download for 7 in. and 10 in. tablets (Apple and Android), and for all desktops. The app was based on the old 'Puff' app that many of us used back in the 80s and 90s. Unfortunately, Puff wasn't maintained that well but can still be compiled on some Linux machines. Thus, we built Z0lver to add on to the features of Puff, while leveraging the benefits of new mobile technology. We have tested many of the designs  from Microwaves101 in Z0lver and heavily used Microwaves101 over the years. We are eager to give back to the community and are therefore hoping that you find the app interesting and worthy of the site. If so, feel free to help point users towards using the app and providing feedback.  We hope to release a version for phones soon and the open source files will be made available at the end of this summer for people to contribute to.

Check out Z0lver at:

Here's two snapshots of a free shirt that Z0lver provided to Microwaves101.  Thanks, guys!

clownhead 400 tshirt back 400


AppCad originated at HP many years ago and is now offered by BROADCOM:

AppCad is very useful to get very quickly engineering answers for transmission lines.


This also from Phil:

Please look at QucsStudio for Windows.

I've tried it and it appears to work for linear, transient, harmonic balance, and also supports Verilog device modelling. QucsStudio is not Qucs. While the two share some developers and they are very similar user interfaces - similar to Agilent ADS, QucsStudio has harmonic balance whereas Qucs does not and QucsStudio has a greater integration with Verilog compilation and support than Qucs. Moreover, QucsStudio appears to be upgraded at more regular intervals than Qucs. The only downside to me is that QucsStudio runs only on Windows and not Linux and has problems with saving projects when used under WINE with Linux.

Or you can check out the list of current features - they probably update their description more often than we do! - at



Puff  was a program developed at CalTech, back in the days when IBM was marketing the original PCs (mid 1980s).  Here is a historical document that describes its use:

R. C. Compton; W. L. Williams; D. B. Rutledge, "Puff, an Interactive Microwave Computer Aided Design Program for Personal Computers"  1987 IEEE MTT-S International Microwave Symposium Digest, pp 707 - 708.

You might be able to find a copy of a second article on Puff here:

Around 2000, someone converted Puff from DOS to Windows. Around 2010, it was offered in version 2.1 for Windows 7.  It does not appear that it has since been updated, and we can no longer find a free copy of it for you to download. However, there is still one site in the UK that still adverstises a Puff for Windows DVD (CD?) for maybe $40 (depends on exchange rates). Use their search tools to look for Puff.

At this point, maybe the world should give up on Puff, and work on developing some modern, free apps. Be careful what you wish for, modern and free mean tons of ads and possibly spyware...


Vipec is free open-source program for analysis of high frequency, linear electrical networks.

Ansoft (Ansys) Designer SV

Ansoft used to provide a free "student version" of their "Designer" software product.  Then they were aquired by Ansys.  Ansys shows a free student version on their web site, but we have not tried it.  Someone let us know if this is useful or not please...

Time domain simulators (Spice)

This from Simon (thanks!) Linear Technologies' (now part of Analog) LTspice IV is free and kicks ass. Note that Analog offers some other great downloads, including a system cascade analysis tool... Editor)

Check out our modest Spice analysis page on Microwaves101 and consider contributing to it!

Qucs and QucsStudio (see above) also perform Spice analysis.

Layout tools


KLayout is open source.  If you ever need to convert between DWG, DXF, GDS files, download it. That's not a request, ist eine bestellung.  Jawohl!


For 3D solid modeling, there is FreeCAD


Autodesk currently offers two free environments, TinkerCad and Sketchbook:



 MatLab-like software

For MATLAB-like software there is Octave, FreeMat, and scilab.  Start looking here:

Author : Unknown Editor