SMITH·BENCH — impedance, lines & matching

Drag anywhere to move the load (◆). Grab the input marker (●) instead and the load is back-solved through the network, so the input lands exactly where you put it.

Network

Top = source side.

Matching solver

Chart overlays

Impedance grid — series parts slide along these Admittance grid — shunt parts slide along these Constant-VSWR circle through the input Constant-Q arcs (Q = |x|/r)

Q

Wavelength ruler

Voltage along the line

forward wave, travelling toward the load reflected wave, travelling back their sum — what a probe measures

Where you are on the chart

The same thing as phasors

Impedance looking toward the load

Line under test

Which line

Z₀ line

Loss dB/λ

Line length: 1.00 λ

Probe, measured from the load: 0.00 λ

Animate ωt Freeze phasors on the forward wave Show current Envelope

At the probe

Both charts take input: drag the ◆ to change what terminates this line, or grab the ● and slide it round the locus to move the probe.

The probe plane is also a point on the Bench chart. Pick one of the network's lines above and it shows up there as a violet marker walking along that element's arc, draggable from either side.

Sweep setup

Start

Stop

Points

RL goal dB

Plot VSWR

Marker:

or click the plot

Band locus

Drag the amber point to move the load until the whole band sits where you want it, or drag the violet one to slide the marker along the trace.

Stub-match drill

Drag the ◆ on the chart to pick your own load.

Line before stub:

Stub length:

Stub end

Self-test — closed-form cases vs. this engine

Every number below is recomputed in your browser at load time. rf_reference.py ships the same cases so you can diff the two engines.

Case	Expected	Computed	Error