Propagation of electromagnetic waves excited by half-wave dipole antenna in time-varying media

In this paper, we first calculate the expressions of radiant electric field excited by the Hertzian dipole in the media under a sudden change. Then we calculate the general expressions of radiant electric field excited by the Hertzian dipole in the media under a series of abrupt time-varying. Since half-wave dipole antenna is a kind of widely used antenna, then the solutions of half-wave dipole antenna in the media under a series of abrupt time-varying are obtained. Emphasis is placed on the frequency shift property of the waves in the time-varying media, and this property is intuitively in this paper as the exciting source in this paper is a conclusive source instead of an impulse used in previous studies.