Gap sources can also be placed on long, narrow, PEC '''Rectangle Strip''' objects to provide excitation for the Surface MoM solver. The gap splits the strip into two strips with a an infinitesimally small spacing between them, across which the ideal voltage source is connected. Only narrow rectangle strip object that have a single mesh cell across their width can be used to host a gap source.
To define a new gap source, follow these steps[[Image:Info_icon.png|40px]] Click here to learn more about '''[[Common_Excitation_Source_Types_in_EM.Cube#Lumped_.26_Gap_Sources | Defining Gap Sources]]'''.
* Right click on the '''Gap Sources''' item in the '''Sources''' section of the Navigation Tree and select '''Insert New Source...''' from the contextual menu. The Gap Source Dialog opens up.* In the '''Source Location''' section of the dialog, you will find a list of all the line and polyline objects in the Project Workspace. Select the desired line or polyline object. A gap symbol is immediately placed on the selected object.* The box labeled '''Direction''' shows the polarity of the voltage source placed on the selected object[[Image:Info_icon. You have the option png|40px]] Click here to select either the positive or negative direction for the source. This parameter is obviously relevant only for lumped elements of active type.* In the case of a gap on a line object, in the box labeled learn more about '''Offset''', enter the distance of the source from the start point of the line[[Common_Excitation_Source_Types_in_EM. This value by default is initially set to the center of the line object.* In the case of a gap on a polyline object, first choose the '''Side''' of the polyline where you want to place the source. Then, in the box labeled '''Offset''', enter the distance of the source from the start point of that side. By default, a gap source is placed at the center of the first side of the polyline object. You can also change the offset value using the spin buttons. If you keep pushing the spin buttons, the gap source moves from one side to the next, and its side index and offset value are adjusted automatically.* In the '''Cube#Defining_Finite-Sized_Source_Arrays | Using Source Properties''' section, you can specify the '''Source Amplitude''' Arrays in Volts and the Antenna Arrays]]'''Phase''' in Degrees.
<table>
<tr>
<td> [[Image:MOM6wire_pic14_tn.png|thumb|360px|EM.Libera's Wire Gap Source dialog.]] </td>
<td> [[Image:MOM6B.png|thumb|360px|EM.Libera's Strip Gap Source dialog.]] </td>
</tr>
</table>
<table><tr><td> [[FileImage:wire_pic14_tn.png]]Â |thumb|500px|A gap source placed on one side of a polyline representing a polygonized circular loop.]] </td></tr>[[Image:Info_icon.png|40px]] Click here to learn more about '''[[Common_Excitation_Source_Types_in_EM.Cube#Defining_Finite-Sized_Source_Arrays | Using Source Arrays in Antenna Arrays]]'''.<tr></table>
=== Modeling Lumped Circuits ===