Qucs: an introduction to the new simulation and compact device modelling features implemented in release 0.0.19/0.0.19Src2 of the popular GPL circuit simulator.

Following the release of Qucs-0.0.18 in August 2014 the Qucs Development Team have considered in detail a number of possible directions that future versions of the software could take. Spice4qucs is one of these routes. Spice4qucs is a Qucs extension that allows Qucs schematics, including non-linear Equation-Defined Device compact models, to be simulated with external SPICE-compatible simulation engines. Qucs-0.0.19Src2 uses ngspice and Xyce for this purpose. The recent release of Qucs-0.0.19Src2 includes the latest spice4qucs extensions and is made available as an experimental feature. All Qucs legacy simulation and modelling features remain unchanged. The spice4qucs extensions introduce in release Qucs-0.0.19Src2 include the majority of the SPICE components distributed with the ngspice and Xyce circuit simulation packages. Circuits can be simulated with Qucs qucsator, ngspice and Xyce in particular circuit investigations can be centred around SPICE, .FOUR, .NOISE, and .DISTO analysis, a SPICE compatible parametrization system employing the SPICE .PARAM statement, SPICE behavioural sources, ngnutneg scripts, and an innovative form of Qucs simulation called “Custom Simulation”. The“Custom Simulation” facility allows uses to develop ngnutmeg scripts for circuit design, compact device modelling, Monte-Carlo simulation (and other related circuit statistical routines) and to process simulation output data. Combinations of these new features significantly increases Qucs simulation and modelling capabilities, particularly in established areas like power/RF electronics and new emerging technologies. Qucs-0.0.19Src2 also introduces a preliminary version of a new Qucs EDD to Verilog-A compact model synthesis tool. This feature is released as a GPL open source software tool in support of current compact modelling research.