== Working with FDTD Simulation Data ==
===Understanding the FDTD Observable Types===Â In [[EM.Cube]]Tempo, project observables are the simulation data that are generated by the simulation engine at the end of each simulation run. [[EM.CubeTempo]]'s FDTD simulation engine calculates all the six electric and magnetic field components (E<sub>x</sub>, E<sub>y</sub>, E<sub>z</sub>, H<sub>x</sub>, H<sub>y</sub> and H<sub>z</sub>) at every mesh grid node at all time steps from t = 0 until the end of the time loop. However, in order to save memory space, the engine has to destroy the temporal field data from each time step to the next and reuse the memory. Storage, manipulation and visualization of 3D data can become overwhelming for complex structures and larger computational domains. Furthermore, calculation of some field characteristics such as radiation patterns or radar cross section (RCS) can be sizable, time-consuming, post-processing tasks. That is why [[EM.Cube]] asks you to define project observables to instruct why types of simulation data you seek in each simulation effort.
[[EM.Cube]]'s FDTD Modules currently Tempo offers the following types of observable:
* '''Field Probe''' for monitoring E- and H-field components at a fixed location in both time and frequency domains.
Of [[EM.Tempo]]'s frequency domain observables, the near fields, far fields and all of their associated [[parameters]] like directivity, RCS, etc., are calculated at a certain single frequency that is specified as part of the definition of the observable. On the other hand, port characteristics like S/Y/Z [[parameters]], VSWR and periodic characteristics like reflection and transmission coefficients, are calculated over the entire specified bandwidth of your project.
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Click here to learn more about the various [[FDTD Observable Types]].
===Defining a New Observable===
* In the case of frequency domain observables, change the observed frequency or frequency range, if necessary.
Once you define an observable, you can always changes its [[parameters]] later from its property dialog, which can be accessed from its right-click contextual menu. You can also delete observables. Â ===Understanding the FDTD Observable Types===Â Click here to learn more about the various [[FDTD Observable Types]].
==Modeling 3D Periodic Structures in EM.Tempo==