In 2013 there was a paper showing how to do Wi-Fi (IEEE 802.11) nearly without power.

The idea was not the one presented in this article, it was more about modulating the electrical properties of the transmitting media. It was a kind of parasitism.

It's like when you stop at a car stop and the radio station you are listening to fades, and when another car comes, then the radio station sound looks resurrected.