Anyone more knowledgeable able to chime-in on the effect of creases here? I couldn’t find any mention of it in the article...
If you can keep the size of the largest crease/feature/defect in your foil smaller than this, you should be okay.
Would love to dig into the science behind this a bit more — I don't really know where to start — i.e. why you're dividing by four.
So as not to waste your time, is there a named phenomenon that you can link me to to learn more about this?
Thanks again!
I would say that you want to be less than 1/10 of the wavelength to minimize the effect though.
That has the look of a rule of thumb, which as a civil engineer that ended up in IT, sounds a bit familiar.
So something like:
Source ----------------------------------- Dest
|
| lambda/4
| stub
By the time the reflection gets back to the transmission line, you have a phase offset of half a wavelength relative to original signal on the transmission line. If you add two signals that are half a wavelength apart, they combine destructively (cancel each other out). So the quarter wave stub acts like a very basic filter, and you actually won't see much of your signal at "Dest" when your transmission line has a quarter-wave stub like this.
Microwave engineers use all sorts of tricks involving transmission line segments that are a quarter wavelength long. So when you're trying to build an antenna (e.g. out of foil, or if you're adding metal support structures to a large antenna), it's helpful to use the heuristic: "if you need to add features that are not part of the original design, try to keep them smaller than a quarter wavelength."
blackguardx is right that restricting the maximum feature size to 1/10 of the wavelength is probably a better rule of thumb if you want good performance. If you can get it down to say, 1/2 of a quarter wavelength (1/8 wavelength), there's a reasonable chance it'll still work.