Wire length and corner radius

[nicknugget]

After stumbling across this great generator, I'm currently looking at the code and tweaking it a bit out of interest. It occurred to me: doesn't the corner radius affect the length of the wire? That's not currently factored into the calculation when I change the radius, is it? Or am I just being dense and it doesn't matter?

[gretel]

if corner radius is 5mm and you're building for 433 MHz (λ ≈ 693mm), the total path reduction of ~8.6mm is about 1.2% of a wavelength = "potentially measurable".

@gaspode-t-wonderdog just noticed, corner_radius=0 gives a jagged corner, but =1 looks fine.

[Sparkiefuchs]

The bend also introduces a tiny inductance increase. Basically a quarter turn winding. Therefore the decrease in wire length is almost negligible. Also a wire bend with Radius 0, is virtually impossible ^^

[gaspode-t-wonderdog]

@gretel I should add more sanity checks, i guess? :)

[gaspode-t-wonderdog]

interesting find :)

i see it this way: bending a copper wire always introduces some radius, whether you're using a frame or not - so just keep the corner radius a small as possible (e.g. 2.5mm for 1mm wire is still fine)

atm I don't really know how to compensate for it... if you want to experiment with this, use version 2 and try with your own values :)

we also experimented with increasing the diameter of the wire channel at the corners, so you can lower the radius but still fit the wire in somehow, but that's not done yet

[nicknugget]

Everything's fine, and thanks for the feedback! I just wanted to know if I was on the wrong track and overlooking something. I don't really have any ideas for a sensible compensation at the moment. It just struck me.

More input checks probably wouldn't hurt, as there are certainly many who approach the matter quite naively.

[Sparkiefuchs]

I mean, I should probably do some NEC simulations, or we just print a few references Antennas with different corner radie. Anyway, I don't think it's the biggest issue, since the antenna itself is resonant over a surprisingly wide range.

But otherwise there is more to optimise, and even more to learn from it. So it's a win in my book.

[gretel]

I mean, I should probably do some NEC simulations

[Sparkiefuchs]

Quite significant, let's try to replicate it in real world.

[gretel]

Quite significant, let's try to replicate it in real world.

please note, my "simulation suite" is experimental, actual significance may vary. agreed, let's validate.