Calculator

S11 to Complex Impedance Calculator

Convert S11 (dB magnitude + phase angle) to complex impedance Z = R + jX. Interactive calculator with formula reference and Smith chart interpretation guide.

Interactive Calculator

S11 → Z Impedance Converter

Reflection coeff |Γ|—
Real part R—
Imaginary part jX—
|Z| magnitude—
VSWR—
Return Loss—

Formula

  Given: S11 = |S11|∠θ
  |Γ| = 10^(S11_dB / 20)
  Γ   = |Γ|·e^(jθ) = |Γ|·cos(θ) + j·|Γ|·sin(θ)

  Z = Z₀ · (1 + Γ) / (1 − Γ)
  R = Z₀ · (1 − |Γ|²) / (|1−Γ|²)
  X = Z₀ · 2·Im{Γ} / (|1−Γ|²)

Common S11 to Impedance Examples

S11R (Ω)X (Ω)Meaning
0 dB at 0°∞0Open circuit
0 dB at 180°00Short circuit
−∞ dB500Perfect 50 Ω match
−10 dB at 0°93.60Real impedance >50 Ω
−10 dB at 90°5047.1Inductive load
−10 dB at −90°50−47.1Capacitive load
RF View S11↔Z Calculator: Built into the RF View Utilities tab — enter S11 dB and phase to get Z, or enter Z to get S11. Works offline, free on Android.

Related Topics

S11 Return Loss

S11 definition

Smith Chart

Visualize S11 as impedance

VSWR Calculator

VSWR/RL/Γ converter

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