E-field + current dumps, general RF interpretation questions

[oberstet]

Hi all,

I'm in the process of designing/modeling a planar helical antenna, and fwiw, I've now got almost all tech parts working for gradually moving to the actual RF problems.

as a RF newbie, pls bare with me, I've got some RF questions, any help appreciated!

cheers,
/Tobias

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to bisect tech problems, I've not only modeled & meshed my planar helical antenna prototype, but also other well known (which mine is not) antennas, and figured out E-field dumps and Paraview rendering:

movie:

https://www.youtube.com/shorts/2anvkk9EtlE

preview:

the antenna is just a regular coiled helix:

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this is great! of course now I want more;)

my newbie RF questions that immediately pop up just from looking at this:

1. I've dumped the E-field from a tight box around the helix .. the winding of the waves is "visually more clear" than when I widen the box to 2x helix radius capturing actually radiated waves .. is that "expected"? here is a video with wide a dump box https://www.youtube.com/shorts/ydX_l9hRt4M
2. the excitation is a single gaussian pulse, and this allows to see the reflection from helix end (I assume one could not really see much of that if using constant excitation?), and the reflection has the opposite orientation compared to the excitation wave. is that "expected"?
3. obviously the reflections are generally unwanted, and in particular in a phase that dampens the excitation wave, is that correct? if so, can I phase shift the phase of the reflection so that its "+ peaks" meet the "- peeks" of the excitation when using constant excitation, ideally reducing disturbing effect of reflections? or even better: is it possible to "short" the waves at the top end of the helix so nothing is reflected? I guess this won't be possible / is a dumb question;) anyways, I do have it.
4. I want to overlay the current distribution within the helix conductor over the E-field emitted/originating from the conductor. the conductor is a PEC wire (1D), whereas I used a cube (3D) as a dump in above. how do I add a current dump on a PEC wire geometry (1D)?

[oberstet]

rgd 4., I have been unable to define a current dump based on the curve of the antenna, but it seems only boxes (planes/cubes) work as dumps.

further, even with boxes as dumps, since the antenna uses a curve as PEC with no width, that didn't work well ... after switching to wire with some width (radius), the current dumping did work (picture/video below) - however this basically made the antenna non-working as it is no longer resonant.

finally I could only get dump_type 3 for total current density (rot(H)) time-domain dump working, not dump_type 2 for electric current time-domain dump.

IOW, I have still failed to achieve both E-field and Current in the same Paraview animation :(

movie:

https://www.youtube.com/watch?v=pRFfFKI08O0

preview:

[oberstet]

one more smaller thing I don't understand is: if you watch the movie you can see yellow pixels sprinkling off the antenna wire into adjacent space - which physically cannot be the case for electrical current .. at least that's my naive understanding. is that a simulation artifact?