NeoFit, thanks lots for that picture. It clear up just a whole lot.
I'd not call that a slot antenna. There's no slot. It function as a form of loop antenna with part of the wire really wide and the other part merely wide. It would be relatively low loss at RF. And the feed point impedance is apparently .035 ohms. I wonder if the conductors are silver plated for best efficiency. That's into a region that ought to match and work pretty well. (And it appears it's short enough resonance is not an issue until fairly high frequencies 15-20MHz.) As a loop it MAY favor radiation to the sides, though. That may not be good. the good thing for it being a loop is it's virtually immune to static electricity.
Anyway - thanks for the picture. It clarified for me "where the current is going."