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Time Domain Transmission Line Simulator (TDTLine)

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This software was created to visually demsontrate the progression of a signal from its source down a transmission line in the time domain. Most transmission line analysis is based on the solution to Maxwells equations under differant physical and boundary conditions and involves a certain amount of interpretation to relate how the signals will behave. This can often lead to transmission line theory to be thought of as a little abstract and difficult to relate to what is actually occuring during the propagation. Such examples are how signals are reflected at boundaries and more importantly the quarterwave transformer.

The Time Domain Transmission Line Simulator (TDTLine) models a series of transmission lines based on the telegraphers equivalent circuit equations and shows simply how a signal is affected by impedance mismatches as it travels along the transmission lines. Displaying the evolution of the signal in terms of voltage, current or transmitted power at all positions on the line, it is a great aid to understanding the principles of microwave transmission lines.




  • Up to 3 Transmission Line segments can be selected with seperate characteristics
  • Various source types, Gaussian, DC Step & Sinusoidal
  • Option to place source at either left, centre or distributed over the first line segment
  • Distributed sources allow traveling wave photodetectors / distributed amplifiers to be demonstrated
  • Built in demonstration features include
    • Quarter Wave Transformer demo
    • Travelling wave source impedance effects (difference between matched an O/C topologies)
    • Travelling wave velocity mismatch demonstations



Developed by G. Rangel-Sharp