.
The dipole is located at the origin , with the current
.
The associated vector potential is
. Appling the relations
and
, the magnetic field can be derived as
. The electric field can then be derived by Ampere’s law
as Hertzian Dipole
Editors：何偉碩、黃旭成
Advisor：江簡富
教授
Consider
a Hertzian dipole which consists of two point charges oscillating around their
center of mass with extreme separation of
.
The dipole is located at the origin , with the current
.
The associated vector potential is
. Appling the relations
and
, the magnetic field can be derived as
. The electric field can then be derived by Ampere’s law
as
In the far field (
), the magnetic field and the electric field will be dominated by the terms
and
. The Poynting vector
in the far-field region can thus be
derived as
, which radiates in the
direction.
and the electric field
distributions and the Poynting
vector
are plotted.