qucs-s-spar-viewer(1)
| qucs-s-spar-viewer(1) | User Commands | qucs-s-spar-viewer(1) |
NAME
qucs-s-spar-viewer - S-parameter data viewer with RF circuit synthesis tools
SYNOPSIS
qucs-s-spar-viewer [OPTION] ...
DESCRIPTION
qucs-s-spar-viewer is an S-parameter data viewer with RF circuit design tools. It is part of the Qucs-S project.
The application supports visualization of S-parameter data from Touchstone files and Qucs datasets, offering multiple plot types including rectangular plots, Smith charts, and polar plots. It includes comprehensive synthesis tools for filter design, matching networks, power combiners, and attenuators.
FEATURES
Data Import
- Touchstone Files
- Read standard .snp files (S1P, S2P, S3P, etc.) supporting frequency sweeps in MA (Magnitude-Angle), RI (Real-Imaginary), and DB (dB-Angle) formats.
- Qucs Datasets
- Import data from both Qucsator (S[i,j] matrix notation) and NGspice (ac.v(s_j_i) voltage source notation) formats.
Visualization
- Plot Types
- Rectangular plots (Magnitude/Phase, Impedance, Stability, VSWR, Group Delay), Smith Charts (Z and Y chart options), and Polar plots.
- Trace Management
- Add, remove, and customize traces with adjustable color, width, and line style.
- Markers
- Place frequency markers with automatic value readout for precise measurements.
- Limit Lines
- Define pass/fail criteria with frequency-dependent limits displayed as shaded regions on plots.
Synthesis Tools
- Filter Design
- Canonical and Direct-Coupled LC filters, transmission line filters.
- Matching Networks
- L-section, stub-matching, and impedance transformers.
- Power Combiners
- Various topologies including Wilkinson, Bagley, Gysel, and Lim-Eom.
- Attenuators
- Pi, Tee, Bridged-Tee and tuned attenuators with power dissipation calculations.
- Netlist Scratchpad
- Text-based tool to simulate S-parameters of a netlist as you type.
All synthesis tools can export circuits to Qucs-S via clipboard for immediate schematic integration.
Session Management
Save and load complete workspaces including all loaded datasets, plot configurations, trace properties, markers, limits, and notes. Session files use the .spar XML-based format.
FILES
- *.snp
- Touchstone S-parameter data files (S1P, S2P, S3P, etc.)
- *.dat
- Qucs dataset files (Qucsator and NGspice formats)
- *.spar
- Session files storing complete application state
AVAILABILITY
The latest version can be obtained from:
https://github.com/andresmmera/qucs-s-spar-viewer/releases/
Online documentation: https://andresmmera.github.io/qucs-s-spar-viewer/
Qucs-S Project: https://github.com/ra3xdh/qucs_s
REPORTING BUGS
Report bugs to the project issue tracker on GitHub or contact the author directly at <andresmmera@protonmail.com>.
COPYRIGHT
Copyright © 2026 Andrés Martínez Mera
This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Licensed under the GNU General Public License v3.0 or later.
AUTHOR
Written by Andrés Martínez Mera <andresmmera@protonmail.com>.
SEE ALSO
qucs(1), qucs-s(1)
| January 2026 | Qucs-S |