Qucs and KiCAD, a great combination

If you do not have the cash to spend into VERY expensive software like ADS from agilent, Microwave Office from AWR...., and you want to do some simple RF/MW simulation or Spice simulation, you can now have the opportunity to load the open source software QUCS (quite universal circuit simulator)

This software gives you the base of a circuit simulator, with examples, technical papers and help which can be downloaded from the QUCS site. It 's very easy to learn, and you also have the opportunity to see what is under the engine, giving researcher an tool where they could add up their contribution.

Another open source software for people wanting to build some PCB is KiCAD, this software may need little more time for the user to understand and use but it can do some very nice PCBs.
When using KiCAD you first need to build your schematic and then import it to your layout using netlist. You can also add some new element into the library, and use the 3D option to visualise your design.

Few bugs are there but they do not stop you from doing some nice board.
One of the bug is that you need to create a library for each new element that you want to add, but this would be probably be fixed by the time that you read this article.

Maybe one more thing is needed would be an good open source EM simulator, a bit more complex task to realised, but I believe that one day...

A great distro for Electronic RF or digital Engineers

Chitlesh Goorah a post graduate student at a French University did some really good work to put together several packages related to electronic design through a distribution called Fedora Electronic Lab .


Based on the new Fedora 8, with an KDE look we can find packages for:

• Sparameters , AC simulation DC simulation or Digital simulation with QUCS, or gEDA

• PCB software with PCB, KiCAD

• you can also do some digital simulation and IC design and layout with the alliance package.

All of these packages are all under open source. The iso CD image of this distribution can be downloaded through the torrent link . It gives you the image of a live CD which would turn your PC into a live EDA platform.
it includes one of my favorite RF software, QUCS.

This distribution helps us to put together all of these package without having to worry about playing with make and command lines.

A great way to encourage more Engineering people to join the open source projects.

thanks to Chitlesh Goorah
and lets help him to continue the good work.

Group delay with Quite Universal Circuit Simulator

Quite Universal Circuit Simulator (QUCS) is a great tool, and one of the best open source RF/Microwave tool I have used so far. It s easy to use simulator for DC, AC, Sparameter, transcient simulator.

It also includes harmonic balance (HB) simulation although work is still needed for this HB to work properly.
Furthermore it has the possibility to include VHDL and Verilog file circuit using the FreeHDL and Verilog Icarus engine tools respectively.

I have used it to calculate the group delay of two simple low pass filter
and I obtained great results (see below)

Note that: My group delay calculation are based on

Gd = - (D(S21)/D(w))
where w = omega in rad/s

You can load the example files at the Qucs web site example
there are examples for AC and Sparameter setup

or directly (right click save as)
Using Sparameter simulation groupdelay_sp.sch
Using AC simulation groupdelay_ac.sch


If you are an RF/Mw geek like me, have a go, you would not regret it.