Your instinct is spot on - it does not, and just does high frequencies in the RF range using acoustic resonance to amplify instead of using electrical amplification. https://en.wikipedia.org/wiki/Acoustic_resonance

One big aspect of this is that is from what can tell, has lower noise and with that a pre-amp/amp that has less noise in the RF domain is epic, it will allow lower power to be used for transmit and also offer longer range at the same power used today. But an amplification that has less noise than existing electrical only options has so many uses that for discovery - I'd rank this up there with graphite.

I should have clarified "acoustic" just means a vibration, like sound, but in this case 274 megahertz, about 14,000 times higher pitch than human hearing... twice FM radio transmissions.

It eventually should result in devices that work past WiFi frequencies.

It doesn't work with low frequencies, it works with very high frequencies but in the acoustic domain. You're looking at wavelengths on the order of micrometers.

It's because the speed of sound (in any material) is much slower than the speed of light (even in high dk materials). To make a selective and low loss filter you want to use resonators which have dimensions which are a large fraction of a wavelength (i.e. a quarter wave). When the wave speed is slower, a wavelength is compressed into less space ( cycles per second / meters per second ) which is what enables the miniaturization.

I believe the acoustic loss in many of these materials is also lower than the dielectric loss in most materials, which also improves filter q and achievable selectivity.

From what they said, an incoming RF signal is converted to acoustic signal. That acoustic signal is probably not in the human audible range. It’s that signal which is filtered and then amplified with this new device, IIUC.