Main screen for Pi – L matching network design / analysis program

Inductor current versus frequency. Y-axis scaling is mA.

Pi-L Matching

Several years ago, I found myself in the middle of designing a high power (100W) output matching network for a HF transmitter. Delving into the mathematics quickly showed how problematic the pi-matching network could be when it came to inductive losses (i.e., heat)! For all of its fine virtues at lower power levels, the pi-network can pose serious power dissipation losses in the inductor if the network-Q is appreciable at all.

This tool makes it very easy to compare L- and pi-matching networks. Not only are the traditional S-parameters and VSWR characteristics computed, but the all-important inductor current is computed as well.

Computed S-parameters

Computed VSWR versus frequency