I agree it sounds impractical. So I looked at the patent -- which not being a radio engineer it's perfectly safe for me to do (n.b. -- it's always dangerous to look at what might be bullshit patents in your field because you open yourself up to increased damages for using common sense). But I was a ham radio operator when I was a kid so I do know the lingo.
There are a number of problems with broadcasting power, starting with the fact that it's inefficient to saturate ambient space with enough radiation to be usefully harvested. But that's not what they're proposing. 802.11 ad operates in the extreme microwave range -- about 5cm wavelength aka the "V" band. This band is also unregulated so you can try weird things in it. What they propose is to use an array of antennas to create a steerable beam -- like a phased array radar. This would confine the power to a specific plane so that you wouldn't have to saturate all of ambient space with power. The beam steering would be done "dynamically", which I take to mean it would figure out how to maximize signal strength with some kind of stochastic algorithm. So it might not work if you are unicycling around the room.
And because the wavelength is so short an antenna array would be relatively compact.
Even so, it doesn't sound that practical. It's bound to be limited to line of sight, for example: the V band does not penetrate walls or the human body at all, in contrast with the S band that conventional wifi operates on. I can certainly imagine applications for it, but making it practical for charging your phone is apt to be very expensive. You'd have surround yourself with V band antenna arrays.
By the way, reading this patent reminds me of why I hate reading patents. They're infuriatingly vague in order to make the claims as broad as possible, and yet are cluttered with inanely obvious details ("the radio receiver can include active and passive components") and irrelevancies (the device may include a touch screen). I think the purpose may be that someone trying to figure out whether the vague language applies to a cell phone will think, "I don't know WTF this is claiming, but look this phone *does* have a touch screen." It just shows how broken our patent system is.