{{Note|Unlike [[EM.Cube]]'s Planar, MoM3D and Physical Optics Modules, the [[FDTD Module]] currently does not support 3D mono-static RCS calculation due to the enormous amount of computational work needed. Only the bi-static RCS is calculated for a given plane wave source.}}
===Running Frequency & Angular Sweeps===Â At the end of an FDTD simulation, an discrete Fourier transform (DFT) is performed on the time domain data, and frequency domain data like S/Y/Z [[parameters]], near field maps and radiation patterns are calculated. If you choose the right temporal waveform for the excitation source, the frequency domain results will have a good degree of accuracy over the specified project bandwidth. Alternatively, you can run a frequency sweep with the FDTD simulation engine, in which the engine is run as many times as the specified number of frequency samples. The center frequency of the FDTD excitation waveform is set equal to each frequency sample at each sweep run, and the frequency domain [[parameters]] are calculated at each frequency sample. This is particularly useful if you want to visualize or animate near field sensors or 3D radiation patterns at different frequencies. To run a frequency sweep, open the FDTD '''Run Dialog''' and from the '''Simulation Mode '''dropdown list select the '''Frequency Sweep''' option. Click the '''Settings''' button next to this dropdown list to open up the Frequency Settings Dialog. Here you can set the values of the '''Start Frequency''' and '''End Frequency''' as well as the '''Number of Samples'''. The start and end frequencies are initially set to default values calculated based on the project's center frequency and bandwidth.<br />Â Â [[Image:FDTD127.png]]Â Figure 1: [[FDTD Module]]âs Frequency Sweep Settings dialog.Â
If your FDTD project has a plane wave excitation, then you can also run an angular sweep. In this sweep, the values of the incidence angles θ and φ are varied at each sweep run. To run an angular sweep, open the FDTD '''Run Dialog''' and from the '''Simulation Mode '''dropdown list select the '''Angular Sweep''' option. Click the '''Settings''' button next to this dropdown list to open up the Angle Settings Dialog. In an angular sweep, only one of the two angles, θ and φ, can be varied at a time. Choose the radio button corresponding to the angle that you want to sweep. Then, set the values of the '''Start Angle''' and '''End Angle''' as well as the '''Number of Samples'''. Under normal circumstances, you would sweep θ from 180°to 90° backward and sweep φ from zero to 360° forward.<br />
[[Image:{{isoimg|FDTD128.png]]Â Figure 2: |[[FDTD Module]]'s Angle Settings dialog.}}
===Defining Custom Output Parameters===