A Review of QucsStudio - Electroagenda

Skip to the content

Search

Search for:

Close search

Close Menu

The prefix Qucs (Quite Universal Circuit Simulator) refers to a family of electronic circuit simulators that can be used for free: Qucs Original, Qucs-S and QucsStudio. All variants have a very powerful and effective graphical interface, which is even better designed than that of other paid tools. This makes this simulator very attractive for all types of users, both for amateurs and in professional environments.

This article focuses on the most ambitious variant, called QucsStudio, and reviews all its design and simulation possibilities. The detailed concepts and images shown below are mostly taken from QucsStudio’s own web site, from its example projects, or from its demonstration videos.

The content is organized as follows:

Toggle

1. Context: Qucs and Variants

This section briefly develops the history of the original Qucs and its evolutions, Qucs-S and QucsStudio.

1.1 Original Qucs

Qucs was originally developed by Stefan Jahn and Michael Margraf among others. Its original goal is to become a full electronic circuit simulator, including typical SPICE simulations (DC, AC, transient) and also those of RF design (S-parameters, Harmonic Balance).

The two main features of Qucs are the following. First, it uses its own simulation engine, Qucsator, which is different from SPICE. It also has a very well designed graphical interface, based on Qt, which provides a very comfortable and effective user interface.

1.2 Qucs-S

Qucs-S (also referred to as Qucs with Spice) extends the original Qucs and allows to use, in addition to Qucsator, free simulation engines based on SPICE (Ngspice, XYCE, SpiceOPus). Its main developers are Vadim Kusnetsov and Mike Brinson.

1.3 QucsStudio

QucsStudio is another circuit simulator that has evolved from the original Qucs project. Developed independently by Michael Margraf, QucsStudio introduces a new simulation engine and adds unique features not present in the other variants such as system simulation, electromagnetic simulation of PCBs, or integration with C/C++, Octave and Kicad.

In practice QucsStudio is the most ambitious version of all those mentioned, with many possibilities for professional use, at least in small environments. The following is an overview of the different types of projects, simulations and co-simulations that can be performed.

2. Graphic Interface in QucsStudio

The following image shows an example of QucsStudio’s graphical interface. The picture shows several sections that are summarized in this section.

As usual, the top horizontal part contains the various menus for operating the tool. Shortcuts to the most frequently used functions (save, launch simulation, move up/down in the subcircuit hierarchy, etc.) are also displayed.

In the left part, vertically, you can select one of the following tabs. The "Projects" tab shows all projects in the working path. The "content" tab shows all simulation files: schematics, codes (VHDL, verilog, C/C++, Octave), results (data and .dpl displays), files with PCBs and others as .html files (see section 6). Next, the "components" tab includes the various generic elements and controllers that can be included in the schematics for the different types of simulation. Finally, the library tab includes specific components from different manufacturers.

In the central part, occupying most of the screen, you can display any of the files mentioned in the previous paragraph for the "Contents" tab. Specifically, in the example of the image, the schematic of a circuit on which a transient simulation is configured is shown. In the schematics, multiple blocks at different hierarchy levels can be made and easily navigated through. The following video shows an introductory simulation of QucsStudio and the navigation through subcircuits at different levels:

Next, during the explanation of the different possibilities of use of QucsStudio, more images and videos are shown that allow you to visualize more details and possibilities of its graphical interface. In addition, section 5 also details the possibilities of the tool to display results.

3. Electronic Design with QucsStudio

The design and simulation of electronic circuits with QucStudio is based on several types of analysis. The controllers for all possible types of analysis are included in the schematic from the "simulations" menu under the "components" tab. They are shown in the following graphic:

The following are the possible types of circuit analysis divided into three sections: analog (including RF), digital and system.

3.1 Analog Circuit Design in QucsStudio

This section shows the extensive analog circuit design and simulation capabilities of QucsStudio. By including support for S-parameters and harmonic balance, QucsStudio extends its possibilities from analog design to RF electronics design.

In addition, in QucsStudio there are several utilities that can...