Interactive Smith Chart
What is a Smith Chart? — graphical tool for complex impedance visualisation SHOW MORE ▸
The Smith Chart is a polar plot of the complex reflection coefficient Γ, with constant-resistance circles and constant-reactance arcs overlaid. Every point on the chart represents a unique impedance Z = R + jX, normalised to a reference impedance Z₀ (usually 50 Ω). The outer boundary is |Γ| = 1 — total reflection. The centre is the perfect match (Z = Z₀, Γ = 0).
Moving along a lossless transmission line traces a circle of constant radius (constant |Γ|) clockwise for movement toward the generator, counterclockwise toward the load.
| Γ | Reflection coefficient = (Z−Z₀)/(Z+Z₀). Complex number, magnitude 0–1. |
| |Γ| | Magnitude 0 (perfect match) → 1 (total reflection). Controls circle size. |
| RL | Return loss = −20 log₁₀|Γ| dB. Higher is better; >10 dB is typical target. |
| VSWR | Voltage Standing Wave Ratio = (1+|Γ|)/(1−|Γ|). 1 = perfect, ≤2 = acceptable. |
| Y | Admittance = 1/Z = G + jB (Siemens). Useful for shunt elements in matching networks. |
Impedance Entry
Reference impedance
Resistance ≥ 0
+ inductive, − cap
Live Readout
Impedance
Z (Ω)—
z (normalised)—
Y (mS)—
Match Quality
|Γ|—
∠Γ (°)—
Return Loss (dB)—
VSWR—
Transmission Line (lossless)
Drag the slider to move the impedance point along a λ/4 (90°) transmission line toward the generator. The |Γ| circle radius stays constant — only the angle changes.
°
After TL
Z (Ω)—
|Γ|—
VSWR—