title: Reexamination of the Doppler effect through Maxwell's equations.
abstract: In this work, the electric field emitted from a moving source, an electric point dipole, is analyzed for the purpose of illustrating the physics behind the Doppler effect. It is found that if the (translational) motion of the source is nonrelativistic, the Doppler effect is realized in two steps: the motion of the source first causes the dyadic Green function associated with the electric field to acquire an oscillation frequency in the far-field region of the source, and then the frequency leads to the Doppler effect. It is also demonstrated that the Doppler effect is observable only in the far-field region of the source.
authors.affiliation: Department of Natural Sciences, Queens University of Charlotte, 1900 Selwyn Avenue, Charlotte, North Carolina 28274, USA. guow@queens.edu
authors.forename: Wei
authors.initials: W
authors.lastname: Guo
authors.forename: Yildirim
authors.initials: Y
authors.lastname: Aktas