I found this article interesting -- even though I don't understand it. Maybe someone can explain it to me?
https://www.electronicdesign.com/analog/piezo-based-approach-dramatically-shrinks-vlf-antennas
I think it is saying that the physical resonance is greatly amplifying the AC voltage applied to the antenna, therefore somehow improving efficiency. But is not one still limited to the low efficiency of a short dipole? And, the energy equation still has to balance, no?
https://www.electronicdesign.com/analog/piezo-based-approach-dramatically-shrinks-vlf-antennas
I think it is saying that the physical resonance is greatly amplifying the AC voltage applied to the antenna, therefore somehow improving efficiency. But is not one still limited to the low efficiency of a short dipole? And, the energy equation still has to balance, no?