RFSim99 is a freeware software that can help you in RF simulation, in your projects, especially if you are trying to design radio filters.
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.
You can download the archived software using the link below, unzip it and then it should work properly. Thanks to Flyb4ck!
Here is how to make RFSim99 work on Windows 7 64-bit OS. You must be running Windows 7 Professional OR Windows 7 Ultimate. Upgrade if you are running anything less. Next, download the Windows Virtual XP Mode for Windows 7 64-bit OS from Microsoft. This will allow you to run any XP program from Windows 7, 64-bit OS. It can be downloaded from Microsoft here: http://www.microsoft.com/windows/virtual-pc/download.aspx . Next, install RFSim99 under the Virtual XP Mode. It works great.
Please write your opinion and give us a feedback in the comments section about this great rf simulator tool. Did you encountered any problems with it?
The video below shows a Touchstone S-parameter s2p file that was generated on a homebrew N2PK VNA being simulated in RFSim 99. The s-parameter s2p file is for a ITT 10.7MHz roofing filter.