"This system relies on an array of antennas that emit radio waves of slightly different frequencies. As the radio waves travel, they overlap and combine in different ways."
This is known as constructive interference, pretty nifty to see it used in this context. The range has been increased from 10 cm to 1 meter since the paper I co-authored on this subject. Impressive!
These kinds of applications have also been a long time coming. With IoT devices and NFC readers looming around the corner, I think it is likely that we will see some pretty innovative medical inventions. Likewise, as mentioned by NKosmatos, we need to take the security aspect very seriously. Some of these NFC devices are programmable, and should defend against attacks that could lead to events such as withholding life-saving medicine or misreporting biometrics.
For reference, check out this paper I co-authored:
Suitability of NFC for Medical Device Communication and Power Delivery (2007)
https://ieeexplore.ieee.org/document/4454171/
And if you're interested in an early paper about RFID-delivered viruses, check out this by Tanenbaum et al.:
What creates interference is difference is phase among waves of the exact same frequency.
It's odd that the paper author is making such basic EM theory mistake, and I wonder what the actual device construction is like. (since it cannot work the way he describes at steady state)
Maybe he's interpreting phase modulation as frequency modulation? Of course at steady state all frequencies would be the same, making this a weird/incorrect interpretation I think.
But then, I'm not an antenna designer, I may have something fundamentally wrong in my understanding. :)
That said, the potential for abuse is limited by what society will tolerate. We tolerate tracking and alcohol monitoring bracelets for people who drive drunk. If we tolerate tracking implants for sex offenders on parole or something I'm sure it'll filter down routine probation sentences eventually.
You can leave your smartphone at home.
why animals? couldn't the researchers just swallow that "prototype about the size of a grain of rice" themselves and/or get several paid volunteers?
Insurance. I assume it's easier to get insurance for human testing if you've shown safety in animals first.
I'd also love to start my car, without having to remember where i left my keys.
More seriously, though, nanotech or relatively small implantables/injectables powered by radio or induction could do a lot for medicine... If anyone could afford it.
Grab enough power to monitor blood sugar, to make sure you aren't putting someone into a coma, but otherwise just try to burn an extra few hundred calories a day.
If you generate a lot of heat... it goes really bad.
