If you’re still looking 2 years later…

I replaced my laptop bluetooth antennae with a short one that I got from Amazon (I had damaged the connector on the original). Just crammed it into some empty space, left the original hanging attached to nothing.

Something like this is what you want: https://www.amazon.com/Hilitand-Internal...

Mine didn’t even have the sticky piece on the end; they were literally just 6 inches of wire with the connector. I’d be willing to gamble $5 it’ll work on a Wii U also.