Transmitters act as sources in a propagation scene. A transmitter is a point radiator with a fully polarimetric radiation pattern defined over the entire 3D space in the standard spherical coordinate system. EM.Terrano gives you three options for the radiator associated with a point transmitter:
* Half-wave dipole radiator* Two orthogonally Orthogonally polarized isotropic radiators
* User defined antenna pattern
By default, EM.Terrano assumes that your transmitter is a vertically polarized (Z-directed) resonant half-wave resonant dipole antenna. This antenna has an almost omni-directional radiation pattern in all azimuth directions. It also has radiation nulls along the axis of the dipole. You can change the direction of the dipole and orient it along the X or Y axes using the provided drop-down list. The second choice of two orthogonally polarized isotropic radiators is an abstract source that is used for polarimetric channel characterization as will be discussed later. Â You can override the default radiator option and select any other kind of antenna with a more complicated radiation pattern. For this purpose, you have to import a radiation pattern data file to EM.Terrano. You can model any radiating structure using [[EM.Cube]]'s other computational modules, [[EM.Tempo]], [[EM.Picasso]], [[EM.Libera]] or [[EM.Illumina]], and generate a 3D radiation pattern data file for it. The far-field radiation patter data are stored in a specially formatted file with a "'''.RAD'''" file extension. This file contains columns of spherical φ and θ angles as well as the real and imaginary parts of the complex-valued far-zoned zone electric field components '''E<sub>θ</sub>''' and '''E<sub>φ</sub>'''. The θ- and φ-components of the far-zone electric field determine the polarization of the transmitting radiator.
{{Note|By default, EM.Terrano assumes a vertical half-wave dipole radiator for your point transmitter set.}}
A transmitter set always needs to be associated with an existing base location set with one or more point objects in the project workspace. Therefore, you cannot define a transmitter for your scene before drawing a point object under a base location set.
[[Image:Info_icon.png|40px]] Click here to learn how to define a '''[[Glossary_of_EM.Cube%27s_Materials,_Sources,_Devices_%26_Other_Physical_Object_Types#Point_Transmitter_Set | Point Transmitter Set]]'''.