# 9: Radiation

- Page ID
- 19450

- 9.1: Radiation from a Current Moment
- In this section, we begin to address the following problem: Given a distribution of impressed current density J(r) , what is the resulting electric field intensity E(r) ? One route to an answer is via Maxwell’s equations. Viewing Maxwell’s equations as a system of differential equations, a rigorous mathematical solution is possible given the appropriate boundary conditions.

- 9.2: Magnetic Vector Potential
- A common problem in electromagnetics is to determine the fields radiated by a specified current distribution. This problem can be solved using Maxwell’s equations along with the appropriate electromagnetic boundary conditions.

- 9.4: Radiation from a Hertzian Dipole
- In this section, we provide a rigorous derivation that the electromagnetic field radiated by a Hertzian dipole represented by a zero-length current moment using the concept of magnetic vector potential

- 9.5: Radiation from an Electrically-Short Dipole
- The simplest distribution of radiating current that is encountered in common practice is the electrically-short dipole (ESD). This current distribution is approximately triangular in magnitude, and approximately constant in phase.

*Thumbnail: Animation of a half-wave dipole antenna transmitting radio waves, showing the electric field lines. (Public Domain; Chetvorno via Wikipedia)*