The S-Parameter Design Tool is a complete two-port S-parameter analysis and feedback design tool for RF amplifier and oscillator design. You can access the tool here:
Features:
- Manual S-parameter entry or import from multi-frequency Touchstone (.s2p) files
- All key amplifier design parameters: stability criteria (K, μ₁, μ₂), stability circles, and simultaneous conjugate matching terminations (Γms, Γml)
- Gain circles: available power gain Ga (source plane) and operating power gain Gp (load plane)
- Unilateral approximation: circles of constant unilateral gain GSU and GLU, plus figure of merit UFOM and gain error bounds
- Noise analysis: circles of constant noise figure and noise measure; Mmin and Γom from closed-form solution
- Device configuration conversion: CE/CS, CB/CG, and CC/CD via Bodway 3-port Z-matrix method
- S-parameter computation with series or shunt feedback at any ΓFB; Fix C/L for frequency-dependent reactive feedback
- Feedback mapping suite: constant-r and constant-x contours in all four S-parameter planes — optimise feedback for gain, stability, or oscillation
- ΓFB plane (reverse mapping): find the feedback termination satisfying multiple design objectives simultaneously
- Publication-quality export: PNG, Touchstone S2P, and LaTeX (pgfplots/smithchart) with all overlays
Developed by Clive Poole with Claude (Anthropic), May 2026.
- [1] C. Poole and I. Darwazeh, Microwave Active Circuit Analysis and Design, Academic Press, Elsevier, Amsterdam, 2016. ISBN 978-0-12-407823-9. ↗ ScienceDirect
- [2] C. Poole and R. Grammenos, “Correct Equations for Minimum Noise Measure of a Microwave Transistor Amplifier,” IEEE Trans. Microw. Theory Techn., vol. 70, no. 2, pp. 1361–1366, Feb. 2022. ↗ DOI 10.1109/TMTT.2021.3129496