Metamaterials - Science topic

I am working on terahertz metamaterials in many reserach paper, a multipole decomposition plots are provided and i don't know how to plot them in CST microwave studio. Mostly researchers shows this analysis for toroidal exciatation in metamatrials. can any one please explain.

I have designed a metamaterial which can function as filter in THz band. So, I am trying to design its equvalent circuit model for this. I have tried but can't get the desire results. Can anybody guide me about this?

What are acoustic metamaterials?

Dear All,

I am trying to define the dispersion curves of a periodic unit cell in COMSOL Multiphysics with prescribed displacements. I am using two separate studies:

- Study 1: Stationary, with prescribed displacements on the four edges of the unit cell.

- Study 2: Eigenfrequency.

I intend to use the results of Study 1 as initial conditions for Study 2.

I also conducted a different eigenfrequency study of the same unit cell, and the dispersion curves from Study 2 and this separate study are similar. This suggests that the results from Study 1 may not have been used as initial conditions for Study 2.

Could I be missing any setup errors?

Thank you in advance

Hello connections, how can we insert the pin diodes in metamaterial surface in CST. The sample of the figure is attached.

your valuable suggestion would be appreciated.

Thanks.

I’m using a Floquet port (only 'Zmax') in CST Studio to analyze an Intelligent Reflecting Surface (IRS/RIS). Are there better options for ports, or has anyone tried using other ports like waveguide, lumped, or discrete ports for similar analyses?

Thanks for your consideration.

I am currently working on the design of an Intelligent Reflecting Surface (IRS/RIS/ metasurface) using CST Studio. I’ve encountered an issue where the S-parameters(S11) show a sudden change at my resonance frequency of 3.5 GHz. This behavior contrasts with what is often reported in IEEE papers, which typically show a smooth transition from 180 to -180 degrees.

My question is if this sudden change is expected or if it indicates a problem with my design or simulation setup ?

Additionally,Are there any process to bias the IRS in cst studio?

I have attached a graph showing the S-parameters for reference.

Let's say we have a standard, regular hexagonal honeycomb with a 3-arm primitive unit cell (something like the figure attached; the figure is only representative and not drawn to scale). The bottommost node is taken as the source of wave input and the ends of the left and right arms are taken as destinations such that Bloch's condition can be applied as q_left = e^ik1 q_bottom and q_right = e^ik2 q_bottom. I wish to learn how would an iso-frequency contour plot be plotted post performing the dispersion analysis. Thanks in advance.

I'm simulating a metamaterial unit cell. I want to plot Frequency Vs Phase Response.

Also I want to extract permeability and permittivity. Kindly share the steps.

And if the purpose of use is achieved, what do we benefit from it?

What is the simplest mathematical model of a mechanical metamaterial that contains rigidity and an external vibration disturbance?

In my mind, there are mechanical oscillatory systems with concentrated parameters. These oscillatory systems are design schemes (may be quite crude, but that's another question) for technical objects whose properties can be represented by a spring, mass, or damper. If an external harmonic effect is applied to the system, then the linear oscillatory system may be in a state of resonance or a mode of dynamic vibration damping. In principle, the concepts of negative rigidity, etc. can be considered within the framework of structural methods. Recently, they have begun to consider metamaterials, the elementary cell of which has some structure similar to some conventional mechanism. The question is, can these mechanisms be modeled using linear oscillatory systems, just as mechanical oscillatory systems are modeled? Are there any such materials? And what does a closed mathematical model of the simplest metamaterial look like?

I have already simulated the design and of course I get absorption rate as 99.91%. how can i calculate the impedance vs frequency for absorber in cst?

What I have found is for any metamaterial absorber, if the effective permittivity is negative at the resonant frequency, then the resonance is plasmonic, and if the effective permeability is negative at the resonant frequency, then the resonance is of the magnetic type. What are the reasons behind this? Again, from the current distribution, it can be decided that the structure shows either electric dipole or magnetic dipole resonance. What is the relationship between these types of resonances in a metamaterial absorber?

Greetings, what literally governs the metamaterial to render epsilon negative or mu negative phenomena. Is there any theory behind finding the same by looking at the structural design of metamaterial unit element without implementing the same in terms of simulations?????????????

I've observed that meta-lenses, which are constructed using nanostructures, exhibit different appearances at times.

Specifically, in Article 1, the meta-lens appears transparent as seen in the graphical abstract of

Conversely, in Article 2, the meta-lens appears white, as depicted in the graphical abstract of

I've observed similar images in other studies as well, not just the examples mentioned above. I'm curious about the reasons behind this variability in appearance. Why do metalenses sometimes appear white instead of transparent?

Furthermore, I'm interested in whether there are any methods to make metalenses appear more like conventional lenses in their appearance.

how to design a zero index metamaterial. what are the initial dimensions of a unit cell? or which dimension or parameter of the unit cell can be changed to obtain a zero index metamaterial.

There is usually airgap between a radiating element and metasurface and I want to calculate the phase delay analytically. Like what is the reflecting phase from the meta? What is the phase delay from the metasurface to the antenna?

Thanks in advance.

Hi

As anybody knows, in bianisotropic metamaterials, the magnetoelectric coupling coefficient will be introduced in these relations:

D=\eps*E+\zeta*H

B=-\zeta*E+\mu*H

where the \zeta is the magnetoelectric coupling coefficient.

The question is how to extract such a coefficient in HFSS. ( That coefficient is not in the field calculator)

I appreciate any response.

I have been trying to reproduce the results of some metamaterial absorber papers using CST Studio 2022. The S parameter results have been successfully reproduced. When I add the E-Field monitor, H-Field monitor, and Surface current monitor at the resonant frequency and run the simulation, the E field and H field results appear, but the Surface current monitor shows nothing. What are the possible reasons for this? How can this problem be solved?

How to find the relative density of the 3D printed cellular structures like honeycomb, double arrowhead?

Hello all,

I'm currently researching metalenses and facing an intriguing challenge.

In my simulations using Lumerical FDTD, based on methods from DOI: 10.1038/ncomms8069, I'm trying to calculate the focus efficiency of metalenses. My process involves placing an aperture at the incident with PML boundaries and measuring the total intensity at the focal point. Initially, I conducted this with only the glass substrate, then repeated with both glass and nanopillars, measuring over an area about three times the FWHM at the focal point.

Here's where it gets puzzling: The intensity with just the glass substrate is consistently lower than with both glass and nanopillars. Interestingly, I also tried the process without any glass substrate at the incident, yet the focal point intensity remained significantly higher than expected.

Could you offer any insights or thoughts on why this might be happening? Your advice or any pointers towards relevant resources would be invaluable.

Thank you for your time and consideration.

Best regards,

while observing the characteristics of zero-index metamaterial like permittivity, permeability, and refractive index, which part of them should be analyzed, the real part, the imaginary part, or both?

I have been trying to find the phase difference to test whether polarization is converted or not in a metamaterial polarization converter. But I am not sure how to do that.

In the below paper, how did the authors got the graph in Figure-3.

We are using floquet port. We used one method where we go to "floquet boundaries' and then tick the box "polarization independent of scan angle phi" and put +45 once and then -45. we then took the S11 of the two simulations (+45 and -45) and then subtracted the phase of these two.

P.S.- I have attached some screenshots of the changes we did to the floquet boundaries. The last image is the phase difference I got following this method. It matches the figure slightly, but I am confused whether my method is correct or not.

Any help is appreciated.

Hello,

I was trying to simulate the given picture's FSS structure in CST. I have drawn the structure, but I am struggling on how to make the port connection for this structure in CST. I have seen many tutorials but all of them contained only one metamaterial. Can anyone tell me how to give port connection on an array of metamaterial, so that I can find the figure shown in the picture?

I understand the physical mechanism of either negative mass or negative bulk modulus of acoustic metamaterial, but paper seems to use analogous electromagnetic model or just equations to demonstrate that "negative refraction needs both negative mass and negative modulus".

However, I am confused about the physical mechanism behind it. Is there any paper or book illustrating this? Thank you.

I want to design a reconfigurable transmit array using varactor diode with metamaterial unit cell. I have gone through many literatures but in most of literature only different design and multiplayers are mentioned to achieve maximum transmission and 360 deg phase tuning. But i am not able to achieve both the things like high transmission and 360deg phase tuning. Could anyone suggest some resources to understand mathematics behind this?

my project title is Enhancement of DGS based UWB Antenna using Multilayer Metamaterial. I've done designing my UWB antenna and got the specification that i need. Metamaterial that i should design suppose to help increase the gain. Other than that, the metamaterial design should act a reflector to the antenna. So that it will help to increase the gain. But, i still stuck to design the metamaterial as the design i made still can't increase the gain of the antenna. Figure below shown how my antenna looks like and a few design that I've been tried before. If anyone know to solve this problem or tell which design could increase the value of the gain, it will be much helpful. Thank you.

my project title is Enhancement of DGS based UWB Antenna using Multilayer Metamaterial. I've done designing my uwb antenna and got the specification that i need. But, i still stuck to design the multilayer metamaterial as shown in figure provided. If anyone know to solve this problem or help to teach on how to design, it will be much helpful. Thank you.

how to decide the orientation of metamaterial in an antenna. for example, if the wave is propagating along the x-axis in an antenna what should be the boundary condition while designing an antenna. should I use floquent boundaries or open boundary conditions.

I might have in my design on CST some overlaps but I couldn't find where it is , so is there any way to know exactly where is it? my design waveguide and metamaterial

An example of achieving negative effective mass density is membrane-type acoustic metamaterials, which exhibit a negative mass density below the cutoff frequency.

We plot it using the formula given. (theoretically)

But now I am facing a problem regarding the negative effective bulk modulus.

Is the Helmholtz resonator capable of showing a negative bulk modulus?

If so, then whether the Helmholtz resonator is an acoustic metamaterial or not

Hi There,

in order to increase antenna gain, meta-material lens is getting popular these days.

I wonder, if we consider size and possible gain of the antenna (limited to size -see the formula in attachment)

- then for a fix size is it possible to increase antenna gain using meta-material lens?

when we apply meta-material lens the overall size of the antenna increase. will it be possible to develop antenna (without meta lens) of bigger size to get similar gain as with using antenna with meta lens?

kindly scholars having experience with meta-material antenna help to get some insight into the size vs gain of antenna using meta-material.

Thanks

Please see the attachment. From the equation, it is clear that for very low frequencies, there will be some regions where STL will be negative. However, negative STL is a violation of energy conservation. Can someone explain this to me?

Hii connection, i have designed a unit cell with boundary conditions, open on x-axis, magnetic on z axis, and electric on y-axis. and simulate the unit cell in the time domain solver. Getting the desired result after optimation. But while I am creating an array, a popup window with the message " it was found that the parametric sweep does not change the structure. For the sake of faster parameter sweep, you may want the single frequency adaptive mesh refinement to be turned off after the first parameter combination has been processed" appears.

DO you want to reuse the refined mesh for all subsequent parameter combinations?

I’m currently in the process of selecting a research topic for my doctoral studies. I have a keen interest in the field of acoustic metamaterials. I would really appreciate if you are helping me to provide your expertise and suggestion to select the topics in the field of acoustic metamaterials

Dear Sir,

The tutorial or user manuals of OptiFDTD say that it can provide reflectivity and transmission properties of metamaterials as a function of incident wavelengths. However, it seems that it can only provide near-field response of the metamaterial instead of far-field, which can be experimentally observed and useful to know the actual validiy of the metamaterials. There should be physical principle to transfer near-field response to far-field response for such materials. It will be appreciated if anyone tell me some functions in the OptiFDTD available for this purpose.

Sincerely yours,

I am designing a metasurface to control the transmittivity and reflectivity of EM waves at a unit cell level by Floquet simulations. Applying this periodic structure to a large panel leads to a high computational effort. In CST there are methods to homogenize the surface using the scattering parameters, but the dependencies on incidence angle and mode are not applicable in FEM and FDTD solvers. I tried to apply GSTC methods and use an anisotropic effective dielectric material definition, but that did not work for well for oblique incidence.

What is the best way of working to homogenize the panel in CST?

Thank you for your recommendations in advance!

How can I check S11 and S21 of a metamaterial unit cell with respect to various phi and theta angle.

Thank you!

My FYP is based on this, kindly if someone can help me out.

Thanks

How can I model the red circle part (Paper with 0.24mm thickness and Air with 6mm thickness) in figure1 (equivalent circuit model) in ADS?

Did I do the right job in figure 2(My model in ADS)?

Is there any component in ADS for dielectric layer in certain thickness?

Somebody please help me solve the questions.

Metamaterials simulation.

Software such as Mirage, Remcom's XFdtd software, OmniSim, etc. exists. but which one is the best for various purposes, for example thermal simulation, acoustic simulation, structural analysis simulation, etc.?

Hello sir/ma'am

I have designed a metamaterial using FR4 substrate of relative permittivity of 4 for C, X, Ku band applications. Now I want to fabricate it for measurement. When I am sending it fabrication, they are providing the FR4 substrate of relative permittivity of 4 at 1GHz. Will it be constant for other frequency or it will vary?

I simulate a periodic structure placed on a lossy, dispersive half-space whose relative permittivity is smaller than zero at some frequencies. Using CST 2020, I apply open boundary condition (without adding space) in the direction filled with the mentioned medium.

However, the simulation doesn't progress due to the errors. These errors are as follows:

1) "The Floquet port boundary at Zmin must be homogeneously filled with isotropic loss-free and non-dispersive material. For non-dispersive materials, please consider using the option to "Ignore losses" in the solver specials.".

2)"The Floquet port boundary at Zmin has negative material coefficients, which are not supported."

Curious to know the reason. Does it belong to the software limitations or sth?

Any suggestions or ideas are appreciated.

Thanks

I want to calculate the absorptivity of a metamaterial absorber. But what is the absorptivity formula in the S-parameter in TE and TM mode ???

What is the value of R and T in terms of the S-parameter in TE and TM mode???

SZmax(1),Zmax(1), SZmax(2),Zmax(1), SZmin(1),Zmax(1)

SZmax(2),Zmax(2), SZmin(2),Zmax(2).........any other

Hello everyone,

is there a generic rule in simulation setup of metamarials cells when it comes to what should be at the bottom of the substrate?

Thanks for your responses.

accurately, i wanna know how to design a transmissive metamaterial cell that produces a wide range of phase differences?

How to use the plane metamaterial lens to realize the function of the dielectric lens (such as convex lens or concave lens), or how to convert the change of the thickness of the dielectric lens into the change of the refractive index of the plane lens, and what is the corresponding relationship between the two

Excuse me  I know how to plot the dispersion diagram of a unit cell, but I want to plot the dispersion diagram of a ribbon supercell.  Do you use an eigenmode solver? What was your periodic boundary condition? For a unit cell all sides become periodic boundaries, What should it be for a ribbon supercell? Is there any change for phase delays between boundaries with respect to a single unit cell? Best regards

Please share reference is any one has. I am looking in terms of antenna design perspective

I am confused about calculating the absorbability of the metamaterial absorber in between the two formulas below.

A=1-R-T ...............(1)

A=1-R ...............(2)

A=Absorbability

R=Reflection

T=Transmission

calculate the absorbability by equation 1 is mostly published metamaterial absorber paper. But nowadays, other authors comment on these papers.

I also want to design a metamaterial absorber. But which is the formula I use to calculate the absorbability of metamaterial absorbers.

I have defined unit cell boundary condition for simulating unit cell of metasurface. If I want to study the reflection phase characteristics of the metasurface then where should be the reference plane in case of floquet port excitation? Should it be coincided at the top layer of the unit cell? Or it should be at Zmax ?

I have studied the literature and found that combining a Helmholtz resonator and membrane results in a negative effective mass density and a negative effective bulk modulus. Typically, in double negative acoustic metamaterials, we find two resonant frequencies, one due to the Helmholtz resonator and one due to the membrane. Is there any possibility that we get only one resonant frequency in double negative acoustic metamaterials?

I would like to know how to simulate the Absorbance of a metamaterial where I vary the Temperature in CST.

Thus, the output of my graph should be Absorbance vs Wavelength/Frequency where the Temperature is varied.

I have observed that some research papers have included ground plane in their design and some have not. What is the purpose of including and removing the ground plane? The ground plane basically reflects the incident wave thus it improves thus the transmission is almost zero in the metamaterial cell. Please help to understand this.

Thank you.

Metamaterials are used in patch antenna as a superstrate increases several antenna parameters like gain, directivity etc. I have read several papers regarding this issue, but couldn't found any proper reason why this parameters are increased? Could you please suggest few papers or explanations based on this issue?

I am working on lattice structures. I saw in some papers that they used nTopolgy software to achieve the structures' stiffness matrix. unfortunately, I do not have access to this software.

You may guide me from which software or what solution I can get this matrix.

I look forward to your kind reply. Sincerely yours

Metasurfaces have been presenting themselves in recent years as promising materials for holography, control of intensity and phase of optical waves, among others; and, in various applications in optics, such as metalens, optical manipulation, 3D image, optical communications and others. What are the advantages (and disadvantages) of holographic metasurfaces in relation to other potential holographic recording medium, such as photorefractive crystals and other photosensitive materials (glasses and polymers)?

I have designed the equivalent circuit of a metamaterial absorber which consists of L, C. S parameter, I got from CST software. Now I want to find out the lumped parameter values. So kindly help me how to find out these parameters value using ADS circuit simulation software?

Hi,

I have designed a metamaterial structure in HFSS software. I am getting S11 below -10db for certain frequency range, but confused with real and imaginary plot of permitivity,permeability and refcractive index. I am sharing the image of structure and plots. Can anyone help me understand if this structure is behaving metamaterial or not.

Thanks in advance.

I want to simulate the developed metamaterial in CST Studio. However, simulation in the Period Structures template does not give me any results. The main aim is to find the permittivity and permeability values from the simulation results. Can someone please tell me what kind of template is appropriate to use and what the settings are?

Please let me know how to draw a color plot of PHP propagation of nanomaterials using mathematical tools. Actually, I am unable to draw phonons propagation using COMSOL. Is it possible to find out the plot using Matlab or other tools?

We want to simulate a metamaterial Antenna in HFSS.

Hi !!

During simulation of space coiling up acoustic metamaterial in comsol acoustic-solid structure frequency domain to retrieve the transmission coefficent ,how could we apply floquet boundary condition for a plane wave.

Can someone show me using some numbers or related simulation file ? for better illustration please see the attached file.

Thanks

Please see attachment, here two terms appeared in the inhomogeneous Helmholtz equation. What is the use of these two terms for a propagating wave in a particular direction.

Imagine the long-term and almost periodical interaction of gravitation waves with existing distribution of atoms (mostly hydrogen) in deep space. Billions of years of interaction can form a repetitive structure of atoms in huge volume (in 3-Dimesions), with some statistical deviations which can be caused by irregularities of gravitation waves.

Can this repetitive structure (in absence of near source of gravitation) represent some properties of Metamaterials?

Hello.

I try to design metamaterials consisting of a split-ring resonator (SRR) to manipulate its polarization.

To estimate polarization control of the metamaterials for any given incident waves, Jones matrix needs to be obtained, which is a matrix related to input/output electric fields in X and Y axis.

Using HFSS, I designed a SRR where two Floquet ports are located at top and bottom of the SRR and master/slave boundaries surround the SRR.

After running the simulation, I can plot S-parameters for several combinations of ports and excitation modes (TE and TM modes).

But, I couldn't find the ratio of transmitted and incident electric fields in X and Y axis which is necessary to identify the polarization states.

Please, let me know how to simulate E-field transmission coefficient of metamaterials using HFSS.