simulation never finishes. fields seem frozen?

How to use openEMS. Discussion on examples, tutorials etc

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boomboompsh
Posts: 3
Joined: Thu 28 May 2020, 04:20

simulation never finishes. fields seem frozen?

Post by boomboompsh » Tue 01 Sep 2020, 20:45

I'm trying to simulate a twin rod transmission line for a class I'm TAing for, and the simulation isn't working.
At about the time the excitation signal finishes, the fields end up like this:
screenshot.png
screenshot.png (37.38 KiB) Viewed 2807 times
and never change. The calculated energy in the simulation progress continually increases. no wave propagates down the line.
I haven't the faintest idea why this might be happening. There was an error about unused primitives, but I managed to resolve that.
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microstriptwinrod.m
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thorsten
Posts: 1460
Joined: Mon 27 Jun 2011, 12:26

Re: simulation never finishes. fields seem frozen?

Post by thorsten » Tue 01 Sep 2020, 21:38

Energy that continuously increases usually means that the PML have gone unstable. The PML are usually the only element that is not inherently stable.
You may try to move them further away and/or make sure the mesh inside of them is homogeneous and in good shape.

boomboompsh
Posts: 3
Joined: Thu 28 May 2020, 04:20

Re: simulation never finishes. fields seem frozen?

Post by boomboompsh » Wed 02 Sep 2020, 22:19

Yeah, I just rewrote it starting from the notch filter example and it somehow became stable. Guess I must have done something to anger the CEM gods. I didn't change much.

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