Aperture excitations may be used to specify a planar, cylindrical or spherical aperture of measured or calculated field values that are impressed as an excitation. The field values are converted into an equivalent array of electric and magnetic dipoles in the solution.
An impressed spherical mode excitation can be defined based on pre-calculated spherical modes. These spherical modes are either radiating to infinity or incident onto a structure , i.e. converging on the coordinate system origin.
This excitation option can thus be used for both the synthesis of an arbitrary electromagnetic field and also for the determination of the response of a receiving antenna due to the incident modes.
The radiation pattern of an antenna may be used as an impressed source from a particular point in space. This radiation pattern may be imported from measured data or from pre-computed far-field solutions.
The respective ideal receiving antennas form the receiving complement to the respective impressed sources. Ideal receiving antennas are good domain decomposition tools when the following assumptions are made:
- The antenna is considered to be matched (i.e. no mismatch loss is taken into account)
- The antenna and model are assumed to have no impact on each other during the solution phase (no coupling is taken into account)
The antenna exists at a particular point in space and has spatial receiving properties of a far-field pattern imported from simulated or measured data.
The antenna consists of near-field apertures that serve as weights for receiving energy via the specified aperture points.
Similar to the far-field antenna, a spherical mode antenna exists at a particular point in space, but is defined by spherical modes, rather than a far-field pattern. The combination of the spherical modes effectively define how energy incident upon it is received by the antenna from any particular direction.