Going beyond Chu harrington limit: ULF radiation with a spinning magnet array

ULF antennas, if made portable within a diameter of 1m, will operate under an electrical length of the order of 10
⁻⁴
to 10
⁻⁶
wavelengths in free space. Like for any other electrically small antenna, Chu's limit kicks in and defines the lower bound of the radiation quality factor. In this paper we present our study on an electromechanical radiating system based on spinning permanent magnets which is not subject to Chu's limit. Based on our simulation study, a spinning magnet antenna array is proposed.