Impedance Matching Calculator: L, Pi, and T Networks

Your details

L-match is simplest. Pi and T give you Q control for filtering or selectivity.
Lowpass uses a shunt capacitor + series inductor arrangement; highpass swaps the roles.
Purely resistive source impedance, e.g. 50 Ohm for standard RF systems.
Ohm
Purely resistive load impedance. Must differ from RS for a match to be needed.
Ohm
Center frequency at which impedance matching is designed.
MHz
Q factorModerate Q
1.73

Quality factor of the matching network at the design frequency

Component 1C1 (shunt, load side) = 13.78 pF
Component 2L1 (series) = 137.83 nH
Component 3N/A (2-element network)
Bandwidth (-3 dB)57.735MHz
1.73
Broadband<2Moderate Q2-5High Q5-15Very High Q15+

L-match designed for 100 MHz, Q = 1.73, BW = 57.735 MHz.

  • The network has a Q of 1.73, which means the -3 dB bandwidth is approximately 57.735 MHz centered at 100 MHz.
  • The L-match Q is fixed by the impedance ratio - to change Q, use a Pi or T topology with a virtual resistance.
  • A Q below 2 gives broadband coverage but less harmonic suppression. This is ideal for wideband power amplifier output matching.
  • All calculated values assume lossless, ideal inductors and capacitors. Real components have parasitic resistance and self-resonance that shift performance at high frequencies.

Next stepSelect standard E12 or E24 series components closest to these values, then simulate the network with a SPICE tool to confirm performance.

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