# DK Card

This card defines an eighth of a sphere, meshed into cuboidal elements, for solving with the volume equivalence principle in the MoM.

On the Construct tab, in the Volumes group, click the  Sphere (DK) icon.

The meshing parameters are set with the IP card, and the medium, as set at the ME card, is assigned to all created cuboidal elements.

## Parameters:

S1
The centre of the sphere.
S2, S3, S4
Specify the three directions S1–S2, S1–S3 and S1–S4, that form the border of the eighth of the sphere. They must be perpendicular to each other and all three must have the same length (the sphere’s radius).
Maximum cuboid edge length
The maximum side length of cuboids along the curved edge (in metres) can be specified. This value is scaled by the SF card. If left empty, the value specified with the IP card is used.
Choose the medium
Select whether the sphere is Dielectric or Magnetic or Both dielectric and magnetic. This is always with respect to the environment. For example if the relative permittivity ${\epsilon }_{r}$ of the cuboid material differs from the environment then this is a dielectric sphere.
Old format (with medium parameters)
For a detailed description of this parameter please see the QU card.
Dielectric bodies treated with the volume equivalence principle (using cuboids) cannot be used simultaneously with dielectric bodies treated with the surface equivalence principle or the FEM or with special Green’s functions.

## Example of DK card usage

The DK card can be used to create a mesh of an eighth of a sphere as shown below.