PCB microstrip line equivalent circuit
QuickField simulation example
This is an example of the microstrip line simulation, performed with QuickField software.
Problem Type
Plane-parallel problem of Transient magnetics.
Geometry
Given
Line length Lz = 5 inches
Voltage source resistance matches the load resistance and matches the load resistance.
Driver voltage pulse magnitude 2V, pulse duration 5 ns, front 0.25 ns.
Task
Calculate voltage pulse propagation in the matched line.
Solution
We use line parameters calculated in Microstrip self impedance example to construct electric circuit:
Lumped inductance L = 67 nH, lumped capacitance C = 7.8 pF.
Load resistance Rload = Source resistance Rsource = PCB impedance Z0 = 92.7 Ohm.
We subdivide circuit in n = 30 segments to simulate pulse propagation.
Distributed-element model inductance L' = L/n = 2.23 nH, capacitance C' = C/n = 0.26 pF.
Result
Time delay is 0.75 ns (per 5 inches). Time diagram of signal propagation.
- Video: PCB microstrip line equivalent circuit
- Download simulation files (files may be viewed using any QuickField Edition).