[[Image:PMOM130.png|thumb|400px|Changing the graph type by editing a data file's properties.]]
[[Image:PMOM134.png|thumb|400px|The S<sub>11</sub> parameter plotted on a Smith Chart graph in EM.Grid.]]
[[Image:PMOM131.png|thumb|300px|EM.Picasso's Smart Fit dialog.]]
[[Image:PMOM133(2).png|thumb|300px|The S<sub>11</sub> parameter plot of a two-port structure in magnitude-phase format.]]
* '''Current Distributions''': Electric and magnetic current amplitude and phase on all metal and slot traces and embedded objects
* '''Near-Field Distributions''': Electric and magnetic field amplitude and phase on specified planes and their central axes
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At the end of an analysis, the 2D quantities usually have a single value that is written into an ASCII data file. Complex-valued quantities are written into complex data files with a "'''.CPX'''" extension. Real-valued quantities are written into real data files with a "'''.DAT'''" extension. Polar 2D radiation pattern data and some other radiation characteristics are written into angular data files with a "'''.ANG'''" extension. In this latter file type, polar data are stored as functions of an angle expressed in degrees. At the end of a sweep simulation of one of the many types available (frequency, angular, parametric, etc.), the ASCII output data files are populated with rows that correspond to the samples of the sweep variable(s). If a sweep simulation involves N sweep [[variables]], then the first N columns of the output data files show the samples of those sweep [[variables]]. All the 2D data files are listed in the '''2D Data Files''' tab of [[EM.Cube]]'s '''Data Manager'''. You can view the contents of these data files by selecting their row in the data manager and clicking the '''View''' button of the dialog.
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3D output data, on the other hand, are defined as functions of the space coordinates and are usually of vectorial nature. Cartesian-type and mesh-type data such as current distributions and near-field field distributions are expressed as functions of the Cartesian (X, Y, Z) coordinates. Spherical-type data like far-field radiation patterns and RCS are expressed as functions of the spherical angles (θ, φ). The 3D radiation patterns are written into a file with a "'''.RAD'''" extension. This file contains the complex values of the θ- and φ-components of the far-zone electric field (E<sub>θ</sub> and E<sub>φ</sub>) as well as the total far field magnitude as functions of the spherical observation angles θ and φ. The 3D RCS patterns are written into a file with a "'''.RCS'''" extension. This file contains the real values of the θ- and φ-polarized RCS values as well as the total RCS as functions of the spherical observation angles θ and φ. The current distributions are written into data files with a "'''.CUR'''" extension. They contain the real and imaginary parts of the X, Y and Z components of electric ('''J''') and magnetic ('''M''') current on each cells together with the definition of all the node coordinates and node indices of the cells. The near-field distributions are written into data files with a "'''.SEN'''" extension. They contain the amplitude and phase of the X, Y and Z components of electric ('''E''') and magnetic ('''H''') fields as functions of the coordinates of sampling points. All the 3D data files are listed in the '''3D Data Files''' tab of [[EM.Cube]]'s '''Data Manager'''. You can view the contents of these data files by selecting their row in the data manager and clicking the '''View''' button of the dialog.
=== Examining Port Characteristics ===
If your planar structure is excited by gap sources or probe sources or de-embedded sources, and one or more ports have been defined, the planar MoM engine calculates the scattering, impedance and admittance (S/Z/Y) [[parameters]] of the designated ports. The scattering [[parameters]] are defined based on the port impedances specified in the project's Port Definition dialog. If more than one port has been defined in the project, the S/Z/Y matrices of the multiport network are calculated. Note that the S/Z/Y matrices of an N-port structure are related to each other through the following equations:Â :<math>\mathbf{ [S] = [Y_0] \cdot ([Z]-[Z_0]) \cdot ([Z]+[Z_0])^{-1} \cdot [Z_0] }</math>Â :<math>\mathbf{ [Y] = [Z]^{-1} } </math>Â :<math>\mathbf{ [Z] = [\sqrt{Z_0}] \cdot ([U]+[S]) \cdot ([U]-[S])^{-1} \cdot [\sqrt{Z_0}] }</math><!--[[File:PMOM121.png]]-->Â where <math>\mathbf{[U]}</math> is the identity matrix of order N, <math>\mathbf{[Z_0]}</math> and <math>\mathbf{[Y_0]}</math> are diagonal matrices whose diagonal elements are the port characteristic impedances and admittances, respectively, and <math>\mathbf{[\sqrt{Z_0}]}</math> is a diagonal matrix whose diagonal elements are the square roots of port characteristic impedances. The voltage standing wave ratio (VSWR) of the structure at the first port is also computed:Â :<math>\text{VSWR} = \frac{|V_{max}|}{|V_{min}|} = \frac{1+|S_{11}|}{1-|S_{11}|}</math><!--[[File:PMOM122.png]]-->
At the end of a planar MoM simulation, the values of S/Z/Y [[parameters]] and VSWR data are calculated and reported in the output message window. The S, Z and Y [[parameters]] are written into output ASCII data files of complex type with a "'''.CPX'''" extension. Every file begins with a header consisting of a few comment lines that start with the "#" symbol. The complex values are arranged into two columns for the real and imaginary parts. In the case of multiport structures, every single element of the S/Z/Y matrices is written into a separate complex data file. For example, you will have data files like S11.CPX, S21.CPX, ..., Z11.CPX, Z21.CPX, etc. The VSWR data are saved to an ASCII data file of real type with a "'''.DAT'''" extension called, VSWR.DAT.
If you run an analysis, the port characteristics have single complex values, which you can view using [[EM.Cube]]'s data manager. However, there are no curves to graph. You can plot the S/Z/Y [[parameters]] and VSWR data when you have data sets, which are generated at the end of any type of sweep including a frequency sweep. In that case, the ".CPX" files have multiple rows corresponding to each value of the sweep parameter (e.g. frequency). [[EM.Cube]]'s 2D graph data are plotted in EM.Grid, a versatile graphing utility. You can plot the port characteristics directly from the Navigation Tree. Right click on the '''Port Definition''' item in the '''Observables''' section of the Navigation Tree and select one of the items: '''Plot S [[Parameters]]''', '''Plot Y [[Parameters]]''', '''Plot Z [[Parameters]]''', or '''Plot VSWR'''. In the first three cases, another sub-menu gives a list of individual port [[parameters]].
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You can also see a list of all the port characteristics data files in [[EM.Cube]]'s Data Manager. To open data manager, click the '''Data Manager''' [[File:data_manager_icon.png]] button of the '''Simulate Toolbar''' or select '''Simulate > Data Manager''' from the menu bar, or right click on the '''Data Manager''' item of the Navigation Tree and select '''Open Data Manager'''... from the contextual menu. You can also use the keyboard shortcut '''Ctrl+D''' at any time. Select any data file by clicking and highlighting its row in the table and then click the '''Plot''' button to plot the graph. By default, the S [[parameters]] are plotted as double magnitude-phase graphs, while the Y and Z [[parameters]] are plotted as double real-imaginary part graphs. The VSWR data are plotted on a Cartesian graph. You can change the format of complex data plots. In general complex data can be plotted in three forms:
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# Magnitude and Phase
# Real and Imaginary Parts
# Smith Chart
In particular, it may be useful to plot the S<sub>ii</sub> [[parameters]] on a Smith chart. To change the format of a data plot, select it in the Data Manager and click its '''Edit''' button. In the Edit File Dialog, choose one of the options provided in the dropdown list labeled '''Graph Type'''.