At the end of an FDTD sweep simulation, other radiation characteristics are also computed as a function of the sweep variable (frequency, angle, or any other user defined variable). These include the '''Directivity (D0)''', '''Total Radiated Power (PRAD)''' and '''Directive Gain (DG)''' as a function of the θ and φ angles. Another radiation characteristic of interest especially in circularly polarized scenarios is the Axial Ratio. In [[EM.Cube]], the axial ratio is always defined in the LCP<sub>z</sub> or RCP<sub>z</sub> sense based on the X- and Y-components of the electric field. In order to calculate the directive gain or axial ratio, you have to check the boxes labeled '''Axial Ratio (AR)''' or '''Directive Gain (DG)''' in the "Additional Radiation Characteristics" section of the '''Radiation Pattern Dialog'''. Four 2D Cartesian graphs of the axial ratio as functions of the theta angle are generated in the three principal XY, YZ and ZX planes as well as the additional user defined phi plane cut. At the end of an FDTD sweep simulation, the directive gain and axial ratio can also be plotted as functions of the sweep variable. In that case, either quantity needs to be computed at a fixed pair of θ and φ angles. These angles are specified in degrees as '''User Defined Azimuth & Elevation''' in the "Output Settings" section of the '''Radiation Pattern Dialog'''. The default values of the user defined azimuth and elevation are both zero corresponding to the zenith.
[[Image:FDTD119.png]]
Figure 1{| border="0"|-| valign="top"|[[File: FDTD119.png|thumb|left|250px|[[EM.Cube]]'s Data Manager dialog showing a list of 2D polar and Cartesian radiation pattern graphs.]]| valign="bottom"|[[ImageFile:FDTD118.png|800px]]Â Figure 2: thumb|left|250px|A 2D Cartesian radiation pattern in the ZX plane cut.]]| valign="top"|[[ImageFile:FDTD117.png|800px]]Â Figure 2: thumb|left|250px|A 2D polar Cartesian radiation pattern in the ZX ZY plane cut.]]|-|}
===Radiation Pattern Above A Half-Space Medium===