This is an interesting paper examining the transmission of DC current as ω→0 in the telegrapher's equation using the Heaviside step function.

Abstract—We explore the question of how direct current (DC) power is transmitted by electromagnetic fields in TEM/Quasi-TEM structures despite the static curl laws ∇ × E = 0 and ∇ × H = J. In this work we treat DC as the long-time limit of a causal step excitation.

https://www.techrxiv.org/users/998334/articles/1358840/master/file/data/Yes__DC_Power_is_Transmitted_by_Electromagnetic_Waves_Preprint_/Yes__DC_Power_is_Transmitted_by_Electromagnetic_Waves_Preprint_.pdf?inline=true

#maxwell #electrodynamics #radio