Sparameters are one of the most important information regarding any passive or active component for RF design, simulation and analysis. To ensure the accuracy and quality of the complex system, RF engineers often deals with Sparameters of many devices and components.
1. AppCad Design Assistant
Supported formats
 Rectangular Plot / Logarithmic magnitude
 Smith Chart
 Polar format
 Smith Chart: Gain/Noise Circle
 Tabular listing (frequency and gain)
 Support multiple files for comparison
 Lumped Balun design and tuning
 Voltage biased circuits
 Current biased circuits
 Small signal and large signal detector
 FET and transistor bias source resistor
 Amplifier efficiency
 Transmission line impedance calculation
 Reflection, Noise, Spurs and Intercept point calculations
 Device thermal calculations
 Engineering constants and Complex Math calculations for RF circuits
 Print plots and results
 Only support 2 port Sparameters
2. RFSim99
RFSim99 is a powerful tool to simulate and analyze simple circuits and plot Sparameter files. It can simulate one port and two port measurements with basic passive elements and it is suitable for simple impedance matching and plotting.
 Linear magnitude
 Logarithmic magnitude
 Smith Chart
 Polar format
 Phase
 Group delay
 Simulate 2 port circuits
 Analyze Sparameter
 Impedance matching
 Only support 2 port measurements
3. RSplot
RSplot simulator is another free tool from RS Microwave Company to plot and analyze Sparameter files. It is very simple and easy to use application which doesn’t requires any installation (application is in exe form). RSplot is suitable to plot multiport Sparameter files in rectangular formats.
 Logarithmic magnitude
 Phase format
 Delay
 Support multiport Sparameter
 Support multiple files for comparison
 Adjust view
 Adjust Frequency /Span
 Markers and Legends
 Print plots
 Only support rectangular plots
4. SPview
 Logarithmic magnitude
 Smith chart
 Admittance chart (Y smith)
 Polar format
 VSWR (only for full version)
 Group delay (only for full version)
 Phase (only for full version)
 Support multiport Sparameter files
 Script support for more functions (full version)
 Schematic analysis (only for full version)
 Remote communicator for instrument connectivity
 Mix mode analysis
Limitation

Full functions only available with licensed version
5. QUCS Simulator
Quite Universal Circuit Simulator is another powerful tool to simulate basic electronic circuits and Sparameters. QUCS is free software under GPL (General Public License) available for all operating systems.
QUCS supports VerilogA compact model standardization for electronic circuit design and macromodelling.
Supported formats
 Linear magnitude
 Logarithmic magnitude
 Smith Chart
 Polar format
 Phase
 Tabular
 Smith – Polar Combination
 3Dcartesian
Options
 Simulation of electronic circuits with component library and macro modeling
 Sparameter simulation
 DC simulation
 AC simulation
 RF Simulation
 Low Pass, High Pass and Band Pass filter design
 Impedance matching
Conclusion
RF system complexity has been increasing and thus the challenges in design and implementation also huge. RF engineers are using sophisticated tools for design, simulation and analysis. I hope the above mentioned software can be used for better understanding of Sparameters, simple analysis and as a handy tool for personal use.
Andy says
I need this program
Pine Pienaar says
Maybe slightly off context, but I recently started using QUCS, a free network simulator in the public domain. Not quite as user friendly but it can take over where RFSim99 ends and has a lot to recommend it for those who cannot afford simulators costing the price of a farm. It could therefore profitably be included in this overview.
I need to produce overlay graphs of work on RF networks. Your excellent overviews gave me exactly what I was looking for. Thank you very kindly!
Pine Pienaar says
Thank you for a blog that introduced me to graphing software with the exact features needed to compliment
the RF network analysis I am doing.
To simulate RF networks, I recently upgraded from RFSim99 to Quite Universal Circuit Simulator (Qucs) which is a freesoftware electronics circuit simulator released under GPL.
It has a graphical user interface that features; schematic capture and data visualization and is able to support all kinds of circuit simulation types, e.g. DC, AC, Sparameter, Transient, Noise and Harmonic Balance analysis as well as pure digital simulations.
It aims to be much simpler to use and handle than other circuit simulators like gEDA or PSPICE and in my opinion it deserves mention in this blog.
Rajiv says
Thanks for your suggestion. We haven’t tried this program (Qucs) yet.
Wiwyam says
I use a really nice free Smith chart tool, it’s great for interactive RF matching and is free and is online!
http://www.willkelsey.com/smith_chart/
John Rogers says
Very interested in these free SWs but I need recommended choice for my particular need. I measure passive components with complex parasitic elements. Even after compensation the high frequency S21 S11 results become noisy. I would like to build lumped lumped element models which can be tweaked to cleanly emulate the overall measurement results. Then use the lumped element model to create the S parameters. In other words I want to filter the data with theoretical model.
Rajiv says
Thanks for your comment. Free software has lot of limitation for detailed analysis of Sparameter characteristics. You may need to consider AWR microwave office or ADS for design and analysis.
Ro man says
This program is powerful and free. I like it https://www.agrfengineering.de/products/software/sparameterviewer/