XGtd^® Main Window

XGtd applies a physics-based propagation model for high frequency analysis of antenna and EMC applications. The graphical user interface allows users to quickly define problem geometry, assign waveforms and antennas, select the desired output, and run the calculation.

Project View

The Project View displays the currently loaded geometry. After the calculations have been run, most of XGtds output can be displayed in the Project View. All drawing is done with OpenGL. Several viewing modes are available: 2D or 3D, wire frame or solid, and in 3D mode: orthographic or perspective. The user has full control over zooming, panning, and rotating in all view modes.

Selection View

When the project geometry is complicated, it may be difficult to get a clear view of a single object or a specific face. The primary purpose of the Selection View is to offer an unobstructed view of specific parts of the geometry. The Selection View possesses all the same view modes and controls as the Project View.

Project Hierarchy

XGtds Project Hierarchy provides a convenient means to navigate within the input and output files of a project. Each level in the hierarchy can be expanded to view the underlying levels. Selecting and right-clicking can be used to access the properties and editing options for most items. The Project Hierarchy is especially useful for viewing and plotting output.

Geometry Editing Tools

Basic objects can be created and modified in XGtd's Object Editor by defining a cross section and extruding the cross section in the z direction. For users specifically interested in chamber design, the chamber create tool defines a chamber geometry by specifying wall locations, heights and corresponding material properties.

Object Importation (DXF, STL)

XGtd requires full three-dimensional object geometries for its ray-tracing algorithm. Complicated object files can be imported directly from DXF or STL files and converted to XGtd object file format. Once an object file is imported, material properties can be quickly assigned to the object.

Object Simplifier

XGtd employs a robust ray tracing algorithm which can be applied to virtually any geometry. However, excessive detail can slow the computations considerably and in some cases even produce less accurate results. XGtds Object Simplifier can eliminate unnecessary detail and put the geometry in the form required by the ray tracing algorithm. The figure on the right shows a typical example of the simplification of an imported object by the Object Simplifier.

Materials

A different material can be assigned to each object or each object face, if desired. Unique colors and display properties can be set for each material in a project.

Waveforms

XGtd allows users to define the following waveform pulse shapes: Gaussian/Gaussian derivative, Blackman, Hamming, Hanning, Tukey, raised-cosine, root raised-cosine, and sinusoid. In addition, XGtd also provides a user-defined waveform type.

Transmitter and Receiver Sets

XGtd defines sources as transmitters and output sampling locations as receivers. Entering these quantities is straightforward in XGtd. Points, routes, grids, and arcs can be defined graphically, or their locations can be read from data files. Antennas are assigned to each set along with the waveform definition. Editing tools allow the locations of Tx/Rx sets to quickly be modified. Each Tx/Rx set can be designated as active or inactive, which determines if it will be used in the next calculation. This eliminates the need to add or delete locations from the data files when making a series of calculations for different active sources.

Antennas

XGtd offers several ways to specify the radiation pattern and polarization of an antenna. The omni-directional and generic dipole patterns are preprogrammed. The direction of the main beam and the rotation about the main beam can be specified, as can a noise figure, and a cable loss factor.

Antenna Pattern Importation

XGtd is capable of importing antenna pattern data from NSMA, Odyssey, MSI Planet, and XFdtd^® files. XGtd also has its own antenna pattern file format through which users can create user-defined antenna patterns.

Databases

XGtd contains antenna, material, and waveform databases. Once added to the database, commonly used components are accessible to all projects and save the user the trouble of entering the same information repeatedly.

Full 3D Propagation Model

The Full 3D propagation model is based on a hybrid SBR/GTD approach developed by Remcom. The Shooting and Bouncing Ray (SBR) method is employed at the start of the calculation to determine the geometrical ray paths within the project geometry. The SBR method has been implemented with robust ray tracing techniques that impose few limitations on the complexity of geometry features. Once the propagation paths have been found, the amplitudes are evaluated using the Geometrical Theory of Diffraction (GTD).

Point-to-Point Analysis

XGtds Full 3D propagation model predicts the paths by which energy travels from the transmitting antenna to the receiving location. XGtds graphical interface makes it easy to view direction-of-arrival, complex impulse response, E-field vs. time, and E-field vs. frequency for each transmitter-receiver link.

Far Zone Antenna Gain

XGtd can calculate the far field antenna pattern of one or more transmitters placed on or near an object. The transmitting antennas are assumed to radiate as point sources, with the pattern of the source antenna assumed to be independent of distance. More than one transmitter can be active at a time, with the antenna gain patterns calculated for all active transmitters.

Interference Analysis

Data for multiple transmitters are also available including Carrier-Interferer ratio, and strongest transmitter to receiver. All predictions are made with full frequency, polarization, and antenna pattern data taken into account.

Propagation Paths

XGtds physics-based Full 3D propagation model is able to predict the paths by which energy travels from the transmitting antenna to the receiving antenna. Ray paths are viewable in the graphical interface for quick interpretation.

Line Plotting

Color-coded displays are frequently a very useful analysis tool, but in many cases the best way of representing data is with a line plot. All output is written to ASCII files with descriptive headers using an easy-to-understand format. All output can be plotted with XGtds line plotting tools. Plots can be saved and reloaded at a later time. Measurements or data from other applications can also be imported into XGtd generated plots.

Output Filters

Output filters isolate ray paths with specific interactions. For instance, a filter can be created for rays that reflect off of features, but do not have diffractions. Rays meeting this condition will be sorted into a separate branch in the output tree. The filter allows the user to identify what objects are the major contributors to the final power received by a set of receivers.