What happens if we take a wire, drill a hole in it and set some current in motion? Will we encounter a magnetic field?

The simplest form of an antenna array are two short dipole antennas. In this problem you will learn how a phase difference between the currents of both antennas affects their combined radiation pattern.

In a limiting procedure, the field of a dipole is calculated. Taylor expansion of 1/r is used.

The electric field of two charges with opposite charge is calculated.