L-Network Impedance Calculator
Design precision matching networks for Complex Loads (R ± jX). This RF Impedance Calculator determines the exact L-Network topology needed to tune antennas, amplifiers, and RF circuits to a standard 50Ω source.
It automatically solves for component type (Inductor/Capacitor), analyzes VSWR, and estimates the Network Q-Factor for bandwidth stability.
Load & Source
InputConfiguration
PrefSolution & Analysis
ResultImpedance Matching Fundamentals
Complex Load (ZL)
ZL = RL + jXL
Real loads (Antennas) are rarely pure resistors. XL must be canceled.Matching Logic
1. Cancel jXL with reactive component.
2. Transform RL to RS.
The tool does both simultaneously.Low Pass
Passes DC and low frequencies. Blocks harmonics.
Preferred for transmitters to reduce interference.High Pass
Blocks DC. Passes high frequencies.
Used when DC isolation is needed (e.g. active biasing).How to Design an L-Network
Define Source & Load
Enter your system’s characteristic impedance (usually 50Ω) in the Source (RS) field. Then, input your measured load impedance (RL and jXL) from a VNA or antenna analyzer.
Set Frequency
Input the operating frequency. Component reactance changes with frequency, so precise values are calculated for the specific band you are using (e.g., 144 MHz for 2m ham band).
Analyze Results
Review the calculated Series and Shunt component values. Check the Tunability Score to ensure the network isn’t too narrow-band (High Q) or impractical to build.