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EM.Cube FAQ

7,290 bytes added, 13:58, 26 August 2022
== EM.Cube FAQ ==
 
Questions/Answers
What formulae are used while calculating the radiation patterns, and other parameters like gain, directivity
The advantage of using PyPlot is that allows you to plot two data set files (with same type, e.g. .CPX) in the same PyPlot graph window as shown in the attached figure. You can have two instances of [[EM.Cube]] program and each have independent PyPlot graph windows.
 
 
 
I read from your website that your software can determine k-beta diagram of periodic structures which is commonly called DISPERSION DIAGRAM. Do you have any model for that purpose? I searched periodic structures and could not find any model.
 
 
To determine k-beta diagram of periodic structures, you can follow our [[EM.Tempo Tutorial Lesson 8: Analyzing A Periodic Frequency Selective Surface]]:
 
http://www.emagtech.com/wiki/index.php/EM.Tempo_Tutorial_Lesson_8:_Analyzing_A_Periodic_Frequency_Selective_Surface
 
and select "Dispersion Sweep" from the Run Simulation window as indicated in the attached figures (KBT1a.png and KBT1b.png). Attached please also find a sample project (KBT1.zip). Please unzip KBT1.zip and run the simulation. You may plot "despersion_sweep_reflection.DAT" and "despersion_sweep_transmission.DAT" from the Data Manager.
 
 
How can I import my own radiation patterns in Terrano *.rad where I have for each antenna in the transmitter and receiver both the co-polarized and cross-polarized radiation patterns? Also, do you have the manual of Terrano?
 
. To import a radiation patterns (*.rad) in [[EM.Terrano]] open the property dialog of the transmitter set (or receiver set) and select the radio button labeled User Defined Antenna Pattern as the radiator type. Then click the Import button of the dialog. The Windows standard Open dialog opens up with the file type set to ".RAD". Browse your folders to find the downloaded pattern file. Select it and click the Open button. You will see the path of the downloaded file in the box next to the Import button.
 
Please see the Importing External Antenna Radiation Patterns for the Transmitter & Receivers section in [[EM.Terrano Tutorial Lesson 8: Simulating A Communications Link With Directional Antennas]]:
http://www.emagtech.com/wiki/index.php/EM.Terrano_Tutorial_Lesson_8:_Simulating_A_Communications_Link_With_Directional_Antennas#Importing_External_Antenna_Radiation_Patterns_for_the_Transmitter_.26_Receivers
You can view [[EM.Terrano]] Manual from the following link:
http://www.emagtech.com/wiki/index.php/EM.Terrano
 
All information on [[EM.Cube]] can be found from [[EM.Cube]] Wiki page
http://www.emagtech.com/wiki/index.php/EM.Cube
 
 
1. Picasso: Is it possible to define Vias that go through more than one layer ?
 
You can define Vias' for each layer in such a way that they are positioned/located on top of one another and are exactly the same.
 
2. Why loss tangent is not automatically specified for known commercial materials, e.g. RO4003C ?
 
Thank you for bringing it into our attention. We will add it in the next released version.
 
3. Is it possible to Copy and object together with rotation/mirror ?
 
Mirror operation keeps the original object and create a new one. Yet, in rotation the original object will change. For this reason you may copy and the rotate the copied object.
 
4. Can [[EM.Cube|EM-cube]] support metal surface roughness (this is crucial for high microwave applications) ?
 
We do not have a parameter for the surface roughness in [[EM.Picasso]]. However, there is a relation between the surface roughness and the effective conductivity. You can use "Conductive Sheet Traces" with the effective conductivity. and rms height instead of "PEC Traces". We will add this option in the next release.
 
1) How do I write the Python Code for my own objects and add it to the simulation? Is it possible to access some part of the code for reference?
 
The following link provide an example how to write a Python script
 
http://www.emagtech.com/wiki/index.php/EM.Tempo_Tutorial_Lesson_7:_Designing_A_Pyramidal_Horn_Antenna#Writing_a_Python_Script_for_Calculation_of_Pyramidal_Horn_Directivity
 
Here is a more detailed information on [[Using Python to Create Functions, Models & Scripts]]
 
http://www.emagtech.com/wiki/index.php/Using_Python_to_Create_Functions,_Models_%26_Scripts
 
2) For modelling of wired antennas, I have used thin wires for respective elements. How will I consider the geometry of a thin wire for calculating current densities in each element? Also, do I have to take only thin wires or while modelling wired antennas or will cylindrical structures do?
 
In [[EM.Libera]], if you open up he Thin Wire dialog, in the property dialog, you can change the define the wire radius from "Wire Radius" box. In other words, it’s a tiny cylinder with small radius of "Wire Radius."
 
Please see "Constructing the Wire Dipole Antenna Geometry" section in the [[EM.Libera Tutorial Lesson 1: Analyzing A Center-Fed Wire Dipole Antenna]]
 
http://www.emagtech.com/wiki/index.php/EM.Libera_Tutorial_Lesson_1:_Analyzing_A_Center-Fed_Wire_Dipole_Antenna#Constructing_the_Wire_Dipole_Antenna_Geometry
 
3) What exactly is the function of a 'Port Definition'? How is it used in calculating the antenna parameters?
 
Ports are defined to calculate the scattering, impedance and admittance parameters of a one-port or multiport structure.
 
Port Definition Observable
 
http://www.emagtech.com/wiki/index.php/Glossary_of_EM.Cube%27s_Simulation_Observables_%26_Graph_Types#Port_Definition_Observable
 
Graphing Port Characteristics & Other Complex-Valued Data
 
http://www.emagtech.com/wiki/index.php/Defining_Project_Observables_%26_Visualizing_Output_Data#Graphing_Port_Characteristics_.26_Other_Complex-Valued_Data
 
4) How do I use the 'Wire gap circuit source' in between two thin wires? If it is not possible, is there any other method of excitation?
 
A wire gap source must always be associated with an existing line object in the project workspace. Please note that when you define your line object say 150 mm, the wire gap source creates an infinitesimal gap on the line, i.e. create two lines of 75 mm length, and connects a voltage source across the gap. All happens behind the scene. Please look at Examining the Gap Source & Simulation Observables in Lesson 1
 
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
 
 
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) ?
 
 
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).
 
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.
Asabet
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