Simulation and Analysis Software Suites

RFSim99 is a free linear S-parameter based circuit simulator offering schematic capture, simulation, 1 port and 2 port S-parameter display and file support, tolerance analysis, stability circles, and much more.It can cost large sums of money to get a workstation seat at some of the high end simulation and analysis software suites. But the underlying mathematics that these programs use is not secret, it is in the public domain and there are low cost or shareware packages that will do the same computations. Often they lack the features and the extensive user interfaces, but the internal engines are running the same equations.
For low frequency or time domain simulations there are versions of SPICE freely available. For RF simulations the field is smaller, but one free program that repeatedly crops up in the listings is RFSim99.
RFSim99 works with S-parameters. This means that not only will it simulate and analyse circuits built out of its internal library of components, but that it can accommodate any circuit block or stage for which these are known. S-parameters are easily measured with a network analyser, so RFSim99 avoids the problems of many packages by not being bound to third party models. As well as the features one would expect to see, such as schematic drawing and graphical analysis, there are a few really good extras, such as an integrated filter design tool and the ability to run tolerance sweeps.
RFSim99 was written by Stewart Hyde. The embedded link to his web site is no longer valid, but at pRF we were so impressed by the program that we tracked him down. | RFSim99
See more details at www.practicalrf.com | | | |