Dear Group
How does one calculate the inductance / capacitance required for an L-match network to enable impedance matching?
Regards Steve.
L-matching (inductance)?
Jan 30, 2005
4 Replies
Additionally, lots of really useful programs mostly dedicated to RF design and calculations at
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Most notably for your question, I suggest the downloads L_TUNER (Calculate coil & capacitor values of an L-Network to match any pair of complex impedances) and Pi_L_Net (Design Pi and Pi-L output networks for RF Power amps)
Dave M
MasonDG44 at comcast dot net (Just subsitute the appropriate characters in
the address)
Never take a laxative and a sleeping pill at the same time!!
If you just want the answer, you could use a calculator such as:
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If you want to understand the theory, try Googling for: matching network series parallel transformation
To analyse a network consisting of inductor L between input and output, capacitor C to ground at the output, and load (RL) in parallel with the capacitor, transform the parallel RC to an equivalent series circuit (Rs-jXs). You now have jwL in series with Rs-jXs. Set wL=Xs to make a pure resistance Rin = Rs looking into the network.
Rs = Xp*Xp*Rp / (Xp*Xp+Rp*Rp) --- eqn 1 Xs = Xp*Rp*Rp / (Xp*Xp+Rp*Rp) --- eqn 2
Where: Rp = Load RL Xp = 1/wC Xs = wL w (omega) = 2*pi*f
Calculate C from eqn 1; calculate L from eqn 2.
You can only solve eqn 1 if RinRL, just put the capacitor at the other end - the network is reversible.
This is the easy way:
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"What is now proved was once only imagin'd." - William Blake, 1793.
Thank you all for your help!
L-match
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