Settings for Dipole Sources #

This section describes settings for dipole sources.

In FDTD, an electric dipole generates a field around the oscillating point charge, while a magnetic dipole exhibits field distribution around a current loop.

Select Dipole in the solver tab and create a dipole in the Composite viewer, then set further parameters in the Edit properties interface that automatically pops up.

Ideal Dipole Field #

In FDTD, a Dipole acts as source $\rho$ for generating the electromagnetic field in Maxwell's equations.

Typical electric and magnetic dipoles are shown in the figure below:

The Monopole, Dipole, Quadrupole, Hexapole, and Octupole can't be accomplished by a simple superposition of dipoles because polarization intensity, $p$ in this case, involves a complex polarization tensor that cannot be described by a superposition of dipoles.

Dipole Settings #

General Settings #

General tab can be used to set properties of a dipole, such as phase shift and rotation. See general settings in Source.

Dipole option allows users to select the desired type of dipole.

Name	Descriptions
Electric	Electric dipole.
Magnetic	Magnetic dipole.

Geometry #

Gemetry tab can be used to set geometric dimensions of a source. See geometry settings in Source.

Wavelength/Frequency #

Wavelength/Frequency tab can be used to set wavelength/frequency of a source. See wavelength/frequency domain settings in Source.

Advanced #

• You can add a Dipole Cloud analysis group in Analysis library to generate a specified number of dipoles, where the position, phase, and direction of each dipole are randomly distributed;
• Non-mesh dipoles can be formed by allocating the data of dipoles on nearby mesh points to the non-mesh dipoles based on distance;
• When simulating non-polarized dipoles, three dipoles with mutual orthogonality must be simulated three times.

Case: Bandstructure of 3D Cubic Lattice #

In this case, a randomly excited Dipole source is used to calculate the bandgap of a photonic crystal. For details, see Bandstructure of 3D Cubic Lattice.