My nephew got a Star Wars thingy for Christmas which is activated
by a small transmitter key being brought close to it. I'm pretty sure
it's the type of thing used for ID chips eg put under the skin of race
horses and other valuable property. My understanding is that the
main unit or wand supplies enough radiated power to the key to
enable it to in turn transmit although over a very short distance (1 or
2cm). The key has a clear case and the PCB is visible. There's a
small (4mm) encapsulated chip and a couple of SMT caps, all
surrounded by a spiral trace that must be the key's aerial. I'd like to
find out more about this technology. But what's it called ?

Jinx