EMTL has several types of radiation sources and technologies for working with them. There are also several time forms of the signal characterizing the radiation from the sources, and it is possible to create your own time forms.

At the same time, the concepts of "radiation source" and "set of radiation sources" exist in EMTL. If in an experiment it is necessary to work with only one type of source and one technology of its operation, then you can not delve into the difference between a "set of sources" and a "source", as well as into the details of working with them. You can simply choose from the examples below the one that suits you and assume that everywhere we are talking just about the source of radiation.

But if it is necessary to work with several radiation sources operating using different technologies or requiring different time forms for themselves, then you will have to understand the details of working with sets of sources.

In EMTL, any source must be included in the set. At the same time, each set should consist only of sources working on the same technology. The final properties of the source consist of its own properties (for example, coordinates) and the properties of the set (for example, the time form of the signal). At the beginning of the work, by default, two sets are immediately created for sources working on two technologies supported in EMTL. Sources are automatically added to them accordingly, unless otherwise specified when creating them.

Currently, two source management technologies are implemented in EMTL, these are:

TF/SF (Total Field /Scattered Field) - correction of fields on the generating surface according to the analytical formula. All sources using this technology will be referred to as TF/SF sources;
Modification of \(\vec{J}(t)\) in Maxwell's equations for given cells. All sources operating using this technology will be referred to as internal current sources.

At the same time, only one set can be created from TF/SF sources in EMTL at the moment, to which one flat TF/SF wave or one or more point TF/SF radiation sources can be added.

Several sets of point sources can be created from internal current sources in EMTL.

Before adding various radiation sources to the experiment, it is necessary to determine the time forms of the signals by adding them to the experiment. You can add one default time waveform or add multiple time waveforms and then associate them with sets of sources. If no time waveform is specified, EMTL sets the default Berenger shape with parameters based on the size of the objects and the size of the counting area.