CST Tutorial - Simulation of a Metasurface Absorber

[@dzulfikarafif3728]

How to calculate permittivity and permeability from it? Just pick s11 and s21 in result template? And choose floquet mode 2?

[@EMSpectrumLab]

Yes, you can use "Result Templates" to extract permittivity and permeability. Floquet mode determines your incident polarization (1 and 2 means TM & TE polarization).

[@gene4094]

This would be nice for the effects of a negative refractive index meta materials that absorbs an infrared beam. A meta material like a catalyst Bismuth ferrite. The refracted field will have a water splitting ultraviolet field, for producing a liquid-phase non equilibrium plasma.

[@EMSpectrumLab]

Thanks for your comment. I'll consider it for future topics.

[@gene4094]

@@EMSpectrumLab this is an oversimplified version of splitting of water. I have presented it to AI Co-Pilot was told to write a scientific paper and submit it to a University. I worked in an analytical Laboratory for 25 years and realized how daunting that would be. If you like, I can give you a paper, though less detailed, on it. I am 76 yo and not good health, but I will do my best to make it logical.

[@kedingChen]

Excuse me, how to set the parameters of complex refractive index material in cst

[@EMSpectrumLab]

When defining new material, in "Dispersion" tab, select "User" & "Dispersion List" for dielectric dispersion and enter your data based on the real and imaginary parts of relative permittivity.

[@attadaphanendrakumar8984]

If I don't have a metal backing and I wanted to consider both absorption and transmission for calculating RL, then while assigning boundary condition do I have use both zmin and zmax as open space? If so then I am getting 8 plots for S parameters, which should be considered as S11 and S12.

[@attadaphanendrakumar8984]

How to identify S21 values in unit cell analysis from CST studio

[@EMSpectrumLab]

Yes, when you do not have a metal backing, you should have both Zmin & Zmax ports. For each port you should assign your desired number of excitation modes. If you set only 1 mode for both Zmin & Zmax you have 4 plots as results (S11, S21, S12 & S22).

[@aimanfizzz4973]

Excuse me, how to do the coding in the matlab and how to import the .txt file in matlab?

[@EMSpectrumLab]

I showed it at 08:58 & 09:39 in the video. To import .txt data to MATLAB you can use "importdata" command. To reach the MATLAB code, you can email me. [e-mail]

[@miguelgarcia2133]

Hello, I'm wondering to know if there is any way to calculate the transmitted electric field, which I guess that maybe it would be easier in time domain. I'm trying to calculate the transmission of certain pillar array structure with CST Studio. I have succeeded with COMSOL but I'm able to reproduce the same results, my guess is that the boundary conditions in CST are wrong. I hope you can help me with this.

[@EMSpectrumLab]

To calculate transmitted wave you should set Zmin as "Open (add space)" boundary condition. Other boundary condition are the same as what I shown in the video.

[@muhammadsajjad-pv6fj]

Hello, sir thanks it's helping me. I have faced a little bit problem when want o calculate the surface current (vector) on the top rings. it does not show anything on the vanadium dioxide surface. how we will get the surface current in vanadium dioxide material?

[@EMSpectrumLab]

For this purpose, you can add new "Field Monitor" and select "H-Field & Surface Current".

[@hamzaasifkhan8421]

Can you please make a video on bistatic vs frequency simulation in CST?

[@EMSpectrumLab]

What do you mean "bistatic vs frequency simulation"?

[@hamzaasifkhan8421]

@@EMSpectrumLab i mean that how can we get the result of bistatic RCS vs frequency graph in CST? Like the monostatic RCS vs frequency graph

[@EMSpectrumLab]

@@hamzaasifkhan8421 Ok, I will record a video about this topic. I would be grateful if you share my channel videos with your friends or anyone who is interested in Electromagnetic Engineering.

[@hamzaasifkhan8421]

@@EMSpectrumLab yeah sure Sir. You’re life savior for new students in the field of EM

[@EMSpectrumLab]

@@hamzaasifkhan8421 🌹

[@attadaphanendrakumar8984]

How to obtain the results separately for TE and TM. I am unable to find that differentiation. Can you please explain it,

[@EMSpectrumLab]

When you set number of Floquet modes, you can determine which mode is excited, TE, TM or both of them. In this structure, due to the symmetry both modes have the same results. I set 1 as number of Floquet modes, so only the result of TE mode was calculated.

[@attadaphanendrakumar8984]

@@EMSpectrumLab if I mention the floquet number to be two the results i am getting S11, S12, S21, S22. Then which I have to consider as the result for TM mode.

[@EMSpectrumLab]

@@attadaphanendrakumar8984 After setting number of modes, you should select TM mode as excitation in that window.

[@attadaphanendrakumar8984]

@@EMSpectrumLab are these modes TE and TM same as TE, TM polarised modes we use in tranfer matrix method? Could you please confirm

[@EMSpectrumLab]

@@attadaphanendrakumar8984 Yes, but for this problem you cannot use transfer matrix to obtain TE, TM modes because of your structure geometry.

[@Md.RezwanAhmedSiam-t9o]

hello sir, can you please provide the matlab code for plotting the electric field distribution??? Thanks in advance

[@EMSpectrumLab]

Please send me an email. [e-mail].

[@muradkabirnipun1101]

Hello May i have the matlab code for plotting reflection, absorption, and transmission all in the same page? Can i maill you?

[@vishwajeetsharan5998]

Hello sir, The studio you are using, is it licensed or without license or is it free?

[@himanshubhatt5704]

sir, do u have a download link for parameters.cst file ?

[@EMSpectrumLab]

You can email me. I'll send the file to you. [e-mail]

[@MoslimUddin-v2y]

Hi sir, you are doing so well. Could you please help me with the simulation vedio of an existing article titled as, " Dual-band tunable perfect metamaterial absorber based on graphene". I have already simulated the structure but found some error.

[@EMSpectrumLab]

You can email me: [e-mail]. Please send your file and mention what your problem is exactly.

[@lavivaswani8611]

sir in Cst how we can export electric field profile of metamaterial if any one know please reply 🙏🏽

[@OOOO_MZamZamBiancaSafilla]

Hello sir, ur video it’s very helping me out. but i wanna ask u, can this tutorial be implemented for an anechoic chamber at s-band frequencies ? i’m very interesting for learning this CST, thank u sir 👏🏻

[@EMSpectrumLab]

Thanks for your comment. Implementing this structure in anechoic chamber have many computational cost, if I can simulate it I will record its video.

[@OOOO_MZamZamBiancaSafilla]

i can’t wait for ur video sir, thank u so much 🙌🏻

[@ASHWANIKUMAR-m4n1z]

Thanks sir for sharing the informative video on THz metamaterial absorber. I have successfully repeated the design. Unfortunately, i am facing problem in plotting the colormap plot. Kindly help me to plot the colormap plot. Thanks

[@EMSpectrumLab]

How can I help you?

[@ASHWANIKUMAR-m4n1z]

​@@EMSpectrumLab Sir, is it possible to share my structure file with you? If possible, kindly le me know. Please help me and see the structure, if i am doing any mistake in plotting the colormap plot. That would be great help for me. Thanks again for your reply.

[@EMSpectrumLab]

@@ASHWANIKUMAR-m4n1z Yes, you can email me. [e-mail]

[@malikgaoua5711]

hi I think your metasurface is a polarization rotator, it is not an absorber if you can look at the cross reflection

[@EMSpectrumLab]

Hi. No, it is not a polarization rotator. To demonstrate this point, simulate the metasurface for both TE and TM modes. You can see cross-reflection is zero.

[@mudrikalaydrus174]

nice design

[@nature.2649]

Vo2 ka temperature parameter kaise change karenge absorber design..

[@nature.2649]

Reply sir

[@wilfridrm9679]

Hello Sir , your tutorial is very interesting. I have a concern about the boundary conditions to be applied on a unit cell. I want to make a transmission metasurface with two phase states (0° or 180°) which means two cells with two possible phase states. Is the x and y condition with unit cell valid?

[@EMSpectrumLab]

Thanks for your feedback. Yes, it is valid.

[@wilfridrm9679]

@@EMSpectrumLab The Unit Cell boundary condition virtually repeats the modeled structure periodically in two directions up to infinity, As I said, I want to do phase distribution with two possible states (0° or 180°) which means that I will have a disordered cell distribution on my metasurface (either a cell with a 180° phase shift or a cell with a 180° phase shift of 0°). Excuse me, but I am a bit confused

[@EMSpectrumLab]

@@wilfridrm9679 Maybe I did not understand what you mean. For your purpose, you should draw whole structure with all unit cells. You cannot assign unit cell boundary. In this situation, I think so the boundary should be Open in both x & y directions.

[@kedingChen]

Hello Sir , How to derive the profile of electric field distribution in the z direction

[@EMSpectrumLab]

Unfortunately, I did not export field distribution before in CST. If I can I'll create a video in the near future.

[@kedingChen]

@@EMSpectrumLab thank you

[@sinman222]

Hello can you tell me what is the configuration of your pc?

[@EMSpectrumLab]

@@sinman222 Core i7, 4710HQ CPU, 12GB RAM

[@johnatkinson2410]

I think you have forgotten to mention that your Z upper boundary was open (add space) yet you never set the space parameter or distance??

[@EMSpectrumLab]

Yes, I didn't mention it but it was shown in the video. It is not required to set the distance, it will be set due to the wavelength automatically by CST.

[@SarWar-o8f]

Can the same design be done in hfss?

[@EMSpectrumLab]

Yes

[@SarWar-o8f]

@@EMSpectrumLab Then please make a vedio about " How to use drude model in HFSS" for designing the same structure! It will be great help to me.

[@EMSpectrumLab]

@@SarWar-o8f I will record its video.

[@SarWar-o8f]

@@EMSpectrumLab okar sir. Thank you. I hope i will get the vedio soon and that will be helpful for completing my thesis on time!❤️❤️

[@tilkesh]

Thank you

[@fahimehhooshyar3875]

Hello, nice job. Please guide me how to simulate metamaterial biosensor with gold SRR in THz frequency on CST. If you make a video about this subject i will be very grateful to you.tnks

[@EMSpectrumLab]

What is your problem in the simulation exactly?

[@fahimehhooshyar3875]

@@EMSpectrumLab I designed teflon(free loss) sub & gold SRR on the sub & analyte layer with e=1.7689, on all of them, but i think results not correct, please give me your email address, i'll send my simulation file there.

[@EMSpectrumLab]

@@fahimehhooshyar3875 [e-mail]

[@fahimehhooshyar3875]

@@EMSpectrumLab thanks, I gmailed you.

[@vishwajeetsharan5998]

Please help me sir Sir can we make this on free cst studio?

[@EMSpectrumLab]

I did not try it.

[@vishwajeetsharan5998]

@@EMSpectrumLab you are using crack version sir or paid?

[@mohammedraihan5617]

For absorbance we need to calculate s21 also.. where is s21??

[@EMSpectrumLab]

In general, the absorbance is equal to A=1-R-T where R=|S11|^2 and T=|S21|^2 are the reflectance and transmittance, respectively. However, since the simulated metasurface has the ground plane, the transmittance and then S21 is zero. So, for simplicity I ignored adding second port to calculate S21 parameter.