JohnLincoln,
From what I understand, the application note adds a mathematical aspect to the idea that a circular antenna needs to be coiled tightly and precisely inducted. So, while I could possibly create an antenna with the range I'm looking for, it wouldn't be easy and there would likely be a lot of wasted material/space.
With that in mind, do you know of any company that produces a big enough circular antenna for my purposes? I've found some companies like this one:
But even that isn't in my range.
On top of that, I can't help but think that even if I buy/make a large enough antenna, the chip/module powerful enough to drive it would be rather expensive/hard to find. Do you think that this would also be the case?