Impedance Matching Calculator
Design an L-network impedance matching circuit to transform one impedance to another at a given frequency.
Ω
Ω
MHz
Q Factor
1.73
Shunt Reactance115.5 Ω
Series Reactance86.6 Ω
Shunt Inductor (if inductive)183.8 nH
Series Capacitor (if capacitive)18.38 pF
Q Factor vs Source Impedance
L-Network Impedance Matching
An L-network uses two reactive components (one series, one shunt) to transform impedances for maximum power transfer.
Formula
Q = sqrt(R_high / R_low - 1)
X_shunt = R_high / Q
X_series = Q x R_low
The shunt element goes across the higher impedance side. You choose inductor or capacitor based on the desired network topology (lowpass or highpass).
Example Calculation
Match 50 ohms to 200 ohms at 100 MHz.
- 01Q = sqrt(200/50 - 1) = sqrt(3) = 1.73
- 02Shunt reactance: 200 / 1.73 = 115.5 ohms
- 03Series reactance: 1.73 x 50 = 86.6 ohms
- 04Shunt inductor: 115.5 / (2pi x 100e6) = 183.8 nH
- 05Series capacitor: 1 / (2pi x 100e6 x 86.6) = 18.38 pF
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