Given that the patent followed a prototype, it has to in some way resemble the final tech.
The fact remains that Ultrasound is not an efficient mode of energy transmission [1]. Wireless induction is almost certainly more efficient over the same distances. And ultrasound is a potential nuisance and hazard to wildlife and pets in way EM broadcasts simply aren't.
The fact remains that Ultrasound is not an efficient mode of energy transmission [1]. Wireless induction is almost certainly more efficient over the same distances. And ultrasound is a potential nuisance and hazard to wildlife and pets in way EM broadcasts simply aren't.
[1] http://dx.doi.org/10.1109/IECON.2011.6119486