Actually i would like to know how can we get S-parameters for a whole metasurface array. Normally due to periodic boundary conditions, we simply simulate the unit cell using floquet port and consider it for a whole array, however, as i wanna bend the metasurface (to a specific central angle), for which, periodic boundaries are not applicable and i need to simulate it using plane wave. One of the paper explains that we need to calculate S-parameters from farfield results (as plane wave provides us with only farfield results) but the process haven't been explained. Therefore, is here anyone who can help me with this query. I would really appreciate your help.
Note: I am using CST software
If you are working with a bent metasurface, periodic boundary conditions and the Floquet port are no longer valid. This case, need to use a plane wave source in CST and place field monitors in front of and behind the structure. By comparing the total field with a free-space simulation, can extract the scattered field.
Cem Güler Thanks for your timely response. Pardon, plane wave doesn't provide S-parameters, it simply gives us farfield results or in other words, it calculates RCS. I am particularly interested to find S-parameters that's why it is only possible using horn antennas. However, i am not expert in this method so i am getting difficulty in it
Hello,
To analyze S-parameters of a metasurface in CST, you must first design the metasurface unit cell and define the simulation environment with appropriate boundary conditions and ports. Next, set up the S-parameter extraction by using the "Template Based Processing" feature in the Post-Processing window to extract the S11 and S21 parameters after the simulation. Finally, evaluate the results, and the extracted S-parameters will be available for viewing in the "1D Results" or "Tables" section of the results tree.
Here are the detailed steps:
1. Design and Setup
- Model the Metasurface Unit Cell:Create the 3D model of your metasurface unit cell in CST.
- Define Boundary Conditions:Apply the appropriate boundary conditions, such as Periodic Boundary Conditions (PBCs) for infinite arrays, or PEC/PMC for single unit cells.
- Set up Ports:Place Floquet ports at the input and output surfaces of the unit cell to excite a plane wave.
- Configure the Solver:Choose a suitable solver (e.g., Time Domain Solver) and define the simulation frequency range.
2. Run the Simulation
- Start the Simulation:Initiate the simulation to solve the electromagnetic fields within the unit cell.
3. Post-Processing and S-Parameter Extraction
- Navigate to Post-Processing:After the simulation is complete, go to the "Post-Processing" tab on the top bar of the CST interface.
- Access Template Based Processing:Select "Template Based Processing" from the dropdown menu.
- Select S-Parameters:Choose the "S-Parameters" option.
- Extract S-Parameters:Choose to extract S11 and S21 by selecting the appropriate options, then click on "Evaluate".
4. Analyze the Results
- View the Results:The extracted S-parameter results, such as S11 and S21 (magnitude and phase), will be available under "Tables" or "1D Results" in the results tree.
- Export Data (Optional):You can right-click on the S-parameters to copy and paste them into a spreadsheet or Matlab for further analysis.
- Thanks
Smrity Dwivedi thanks for your detailed response but i am asking about the whole array simulation to analyze it's S-parameters. Unit cell will give us the results for infinite array but i want to analyze the finite array that is also fabricated
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