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Loads in Network Schematic

Hello together,

I try to simulate a simple transmission line system with and without a ground plane to verify the MTL theory.

To do so, I need to define current sources and load resistors at both ends of each line, as it is required for MTL theory.

But in the network schematic I can't use loads and sources. I do not want to construct wires from the MTL endings to the ground plane, since they generate additional crosstalk.

How would you do that? I tried to use cables and wires, but both solutions seem to be not sufficient.

Maybe someone knows how to do that. I would be happy to know.

Best regards

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Feko

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Mel

In the below image, I modified the Example Guide model D-02 to remove the monopole and added a Voltage source in the cable schematic to the MTL cable.

Seems simple, or did I misunderstood your question perhaps?

<?xml version="1.0" encoding="UTF-8"?>

Elektrolysator

Thank you very much for your answer.

I need to enlarge the distance to PEC ground >>> 0.2 wavelengths. My solver does not like that in the case I use cables.

Thus, I use wires. It seems to work, if I use a SPICE network as load network, but I do not know, how to implement a source in the network schematic.

<?xml version="1.0" encoding="UTF-8"?>

Mel

For non-radiating network sources, the source is applied outside of the schematic by choosing the network port in the voltage source dropdown box.
For example, in Example Guide example E-3:

<?xml version="1.0" encoding="UTF-8"?>

Elektrolysator

Great! This works.

So, there ist just one point remaining. Can I set the port voltage to 1 MV and add a Network of a single resistor with 1 MOhms in series to generate a current source with 1 Ampere? The input impedance should be much smaller.

Mel

Yes you can.

Elektrolysator

Ok, this worked so far. I still wonder why the cable simulation and the wire simulation give very different results.

In the example, I compare the current at the front end of cable/wire 2. In this case I use a constant voltage source rather than a constant current for simplicity.

Maybe anyone knows where the difference comes from since the physics should be the same: cable 1 radiates and cable 2 and 3 act as receiver.

Unable to find an attachment - read this blog

Mel

One cable harness does not couple to another cable harness.

You would have to put cables that you want to couple in the same cable harness.

See 'Defining a cable harness' in the User Guide and the cable coupling properties choices.

Mel

To clarify, you should put the two cables that are close to each other in the same harness. This will allow them to have LC coupling in the MTL method.

If you want, for example, to excite the harness with the 2 cables inside the same harness, and have the 3rd cable (2nd harness) receive signal from the 1st harness, set it to irradiating. It will then receive via the radiated fields from the harness with the 2 cables. Again, see the cable coupling options.