alt Hacker NewsIf you find that fascinating already... did you know that all cellphones use mechanical filters in the GHz range? They combine very good performance with very low energy consumption.
https://en.wikipedia.org/wiki/Surface_acoustic_wave
https://de.wikipedia.org/wiki/Akustische-Oberfl%C3%A4chenwel... (pictures)
Honestly, the "HF physics is black magic" trope has made me numb to the phantastical contraptions. I appreciate when they look cool, like esoteric orgon wave radiators.