[smith-chart-basic] Smith Chart for RF/Impedance

[MarkusNeusinger]

Description

A Smith chart for RF engineering showing impedance and reflection coefficient on a specialized circular grid used in microwave and antenna design.

Applications

• RF impedance matching
• Antenna design visualization
• Transmission line analysis
• Microwave circuit design

Data

• frequency (numeric) - Frequency points (Hz)
• z_real, z_imag (numeric) - Complex impedance
• Or: gamma_real, gamma_imag - Reflection coefficient
• Reference impedance: typically 50 ohms

Notes

• Standard Smith chart grid (resistance circles, reactance arcs)
• Plot impedance locus vs frequency
• Normalized to reference impedance
• VSWR circles (optional)
• Frequency labels on curve

[claude]

✅ Spec ID: smith-chart-basic

Rationale: A Smith chart is a specialized polar diagram with unique constant-resistance circles and constant-reactance arcs used exclusively in RF engineering and impedance analysis - this is a valid and unique plot type not covered by existing specs like polar-basic or radar-basic.

Add label approved to begin generation.

[github-actions]

✅ Specification Ready: smith-chart-basic

PR: #3801

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specification.md

smith-chart-basic: Smith Chart for RF/Impedance

Description

A Smith chart is a specialized circular diagram used in RF engineering to display complex impedance and reflection coefficients on a normalized polar grid. The chart features constant resistance circles (centered along the horizontal axis) and constant reactance arcs (curving from the right edge), enabling engineers to visualize impedance matching, transmission line behavior, and antenna characteristics. It reveals relationships between impedance, admittance, and reflection coefficient that would be difficult to interpret in Cartesian coordinates.

Applications

• Designing impedance matching networks for RF circuits and antennas
• Analyzing transmission line impedance transformations along electrical length
• Visualizing complex S-parameters and reflection coefficients in microwave circuits
• Optimizing antenna feed point matching to minimize VSWR

Data

• frequency (numeric) - Frequency points in Hz for impedance measurements
• z_real (numeric) - Real part of complex impedance (resistance in ohms)
• z_imag (numeric) - Imaginary part of complex impedance (reactance in ohms)
• z0 (numeric, optional) - Reference impedance for normalization (default: 50 ohms)
• Size: 10-200 frequency points recommended for smooth impedance locus curves
• Example: S11 measurements from a vector network analyzer across 1-6 GHz

Notes

• Draw standard Smith chart grid with constant resistance circles and constant reactance arcs
• Normalize impedance values to reference impedance (Z/Z0) before plotting
• Plot impedance locus as a connected curve showing frequency sweep trajectory
• Add frequency labels at key points along the impedance curve
• Optional: Include VSWR circles (constant reflection coefficient magnitude)
• Chart boundary represents |gamma| = 1 (total reflection)
• Center of chart is matched condition (Z = Z0, gamma = 0)

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Next: Add approved label to merge this specification to main.

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🤖 spec-create workflow

[github-actions]

🚀 Specification Merged!

Specification: smith-chart-basic
PR: #3801 (merged)

The specification is now in main and synced to PostgreSQL.

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Next: Add generate:{library} labels to start generating implementations.

Available libraries: matplotlib, seaborn, plotly, bokeh, altair, plotnine, pygal, highcharts, letsplot

Or use workflow dispatch for bulk operations.

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🤖 spec-create workflow