What does it mean if energy never seems to dissipate?

[thehans]

I am simulating an antenna and have set the energy limit to 1e-4, but it never quite makes it there. It slowly dips to around -37dB at lowest, then seems to rise back up to -34dB before running out of time steps, which are >1000 * Excitation signal length

Does this indicate anything in particular that could potentially be wrong with my setup?

Full log of latest run attached
energy.log

[gadiLhv]

You really didn't need to paste the entire output... You can just attach the et and ht files.
More importantly, you didn't add the setup that actually caused this.

However, I'm going to make a leap of faith here, and assume that this is a very narrow band structure, with low losses. That what you are probably seeing is the structure ringing for a very long while.

Either add losses to the system, or accept the limitations of transient simulations...
I know that openEMS can also converge to steady state, but I am less familiar with that.

[thehans]

Sorry. I've edited the original post to just attach the log info. The temporary et/ht files have already been deleted.
Its actually a ultra wideband vivaldi antenna I'm attempting to model.
I was using all MUR boundaries, but after reading that these can be unreliable, I've switched to PML_8 with added margin to the outer mesh and that has resulted in quicker dissipation.

I'm cleaning up some cruft in my setup script and plan to post it later to my other discussion thread regarding this model(to avoid cluttering discussions), for any further advice #378