== EM.Cube FAQ ==
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Questions/Answers
What formulae are used while calculating the radiation patterns, and other parameters like gain, directivity
http://www.emagtech.com/wiki/index.php/EM.Libera_Tutorial_Lesson_1:_Analyzing_A_Center-Fed_Wire_Dipole_Antenna#Examining_the_Gap_Source_.26_Simulation_Observables
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1. How do i set simultaneous excitation of multiple ports ?
2. Can i use amplitude of -1 in order to create a 180 phase shift between ports in the FDTD simulation ?
otherwise, how can i stimulate 2 ports with 180 degrees phase shift ?
3. Can i choose some ports to be stimulated and others with no stimulation (just as a termination) ?
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You can define multiple sources that will set the corresponding ports. In [[EM.Cube]] amplitude of the source should not be negative. For this reason, in order to introduce phase shift of 180 deg., you can click on "Waveform..." button in the "Source Properties" section of a Source dialog window. In the "Excitation Waveform" dialog window, set the Amplitude to 1 and the Phase to 180. Similarly, by setting the Amplitudes of some sources to 0 (zero) you can let some ports to be stimulated while those with zero amplitude without any stimulation (terminated).
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To calculate S11-S12, you can do post-processing by getting them into Python. You can perform some operations (add, subtraction ...) on RCSs, Radiation Patterns, Field Sensors, etc. Yet, we do not have any Python function for S-parameter operations. We will implement some new Python in the next [[EM.Cube]] release.