Science topic

Metamaterials - Science topic

Metamaterials are artificial materials engineered to have properties that may not be found in nature.
Questions related to Metamaterials
  • asked a question related to Metamaterials
Question
2 answers
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
Relevant answer
Answer
Here's another list for you Mk Karthi .
  1. Adaptive Acoustic Cloaking: Investigate the development of adaptive acoustic cloaking devices capable of real-time response to changing acoustic conditions. Explore applications in sonar technology and materials science for enhanced stealth capabilities.
  2. Metamaterials for Urban Noise Mitigation: Research acoustic metamaterials designed to reduce noise pollution in urban environments. Focus on sound-absorbing and deflecting structures to enhance acoustic comfort and urban sustainability.
  3. Quantum Acoustics with Metamaterials: Explore the use of metamaterials in the emerging field of quantum acoustics. Investigate how metamaterials can manipulate quantum acoustic phenomena, potentially leading to advancements in quantum information processing.
  4. Advanced Ultrasound Imaging with Metamaterials: Develop acoustic metamaterials to improve ultrasound imaging resolution and depth. Investigate the design of acoustic lenses and sensors for enhanced medical diagnostics and healthcare applications.
  5. Underwater Acoustic Exploration: Pioneer the use of acoustic metamaterials for underwater exploration, including improved sonar and underwater communication systems. Explore applications in marine research and defense technology.
  6. Acoustic Solutions for Space: Research the application of acoustic metamaterials in space habitats and spacecraft to address noise and vibration challenges. Enhance the acoustic environment for astronauts during space missions.
  7. Bio-Inspired Acoustic Metamaterials: Draw inspiration from natural structures to create bio-inspired acoustic metamaterials. Investigate their potential for advanced sensors, biomimetic materials, and underwater communication systems.
  8. Acoustic Energy Harvesting: Explore the development of acoustic metamaterials for energy harvesting, converting acoustic energy into electricity. Investigate applications for sustainable power generation in remote or off-grid areas.
  9. Quantum-Secure Acoustic Communication: Research quantum-secure acoustic communication networks using metamaterials. Explore the potential for unbreakable acoustic encryption methods with applications in secure communication.
  10. Metamaterials in Extreme Environments: Develop metamaterials for use in extreme environments, such as deep-sea exploration, space travel, or industrial settings with high temperatures and pressures. Investigate their resilience and adaptability.
  • asked a question related to Metamaterials
Question
2 answers
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,
Relevant answer
Answer
As of my last update in September 2021, OptiFDTD (Finite-Difference Time-Domain) is a software tool primarily used for simulating and analyzing the behavior of optical devices and structures in the time domain. It is part of the Optiwave software suite. While OptiFDTD is a powerful tool for studying various optical phenomena, it may not directly provide "far-field reflectivity and transmission spectra" for metamaterials as a built-in feature.
In OptiFDTD, you can simulate the behavior of optical metamaterial structures and analyze various properties such as transmission, reflection, and near-field distributions. However, obtaining the far-field spectra (which typically involves Fourier transforming the near-field data) might require additional post-processing steps or using other software tools for further analysis.
To obtain far-field reflectivity and transmission spectra for metamaterials, you can follow these general steps:
1. **Near-Field Simulation:** Set up your metamaterial structure in OptiFDTD and run simulations to obtain the near-field distributions (e.g., electric field or intensity) at specific frequencies or over a range of wavelengths.
2. **Far-Field Transformation:** After simulating the near-field distributions, you need to transform the near-field data into the far-field domain to obtain the spectra. This transformation involves Fourier transforming the near-field data to obtain the angular and spectral components of the radiation pattern.
3. **Post-Processing or External Tools:** Perform post-processing on the transformed far-field data to obtain the desired reflectivity and transmission spectra. You can use software like MATLAB, Python, or other data analysis tools to handle the Fourier transformation and further analysis.
Keep in mind that the process may vary depending on your specific simulation setup and the type of metamaterial you are working with. Additionally, OptiFDTD might have received updates or added features since my last update, so I recommend checking the latest documentation or contacting the software vendor to see if there are any built-in features or plugins that can help with far-field analysis for metamaterials.
Always ensure that the simulation setup, post-processing, and analysis methods you use are accurate and validated against known results or experimental data to ensure the reliability of your findings.
  • asked a question related to Metamaterials
Question
6 answers
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!
Relevant answer
Answer
Sorry, for my delayed reply. I had some days off.
Thank you again for your explanation, Thomas. According to that, I would rather keep the higher level few. My concern is about radio frequencies anyway.
I managed to synthesize effective parameters that widely match the wanted responds. I guess the mismatch is due to the limits of the software and can be hopefully sorted out with the vendor's support.
  • asked a question related to Metamaterials
Question
3 answers
How can I check S11 and S21 of a metamaterial unit cell with respect to various phi and theta angle.
Thank you!
Relevant answer
Answer
Muhammad Sajjad I can't find theta and phi in the parametric sweep option. It only shows the design-related parameters to perform parametric sweep operations. Can you please mention it a little bit more clearly? Thank you!
  • asked a question related to Metamaterials
Question
2 answers
My FYP is based on this, kindly if someone can help me out.
Thanks
Relevant answer
Answer
Dear Syed Osama Bin Sadiq , very important in your question the sign of the refractive index as well.
As start point of your research you can considare fig. 4 in the conference paper
  • asked a question related to Metamaterials
Question
3 answers
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.
Relevant answer
Answer
Now i use the ideal transmission line model to instead of paper and air. the impedance is calculated by the permittivity and permeability. The electrical length of the transmission line is calculated by the thickness and the impedance@Thomas Breuer
  • asked a question related to Metamaterials
Question
4 answers
some edges which are part of lossy conductor surfaces are the intersection of otherwise disjoint regions. these edges will be treated as infinitely thin PEC wires
Relevant answer
Answer
okk, I get your point, sir. thank you again for your answers. @Malcolm White
  • asked a question related to Metamaterials
Question
9 answers
Metamaterials simulation.
Relevant answer
Answer
How is Comsol simulation different from fdtd simulation?
  • asked a question related to Metamaterials
Question
6 answers
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.?
Relevant answer
Answer
There are several software options available for designing and simulating metamaterials for various applications. Some popular options include:
  1. Comsol Multiphysics: This software offers a wide range of tools for simulating electromagnetic, acoustic, and thermal phenomena, making it well-suited for designing and simulating metamaterials for various applications.
  2. Ansys HFSS: This software is specifically designed for simulating high-frequency electromagnetic fields and is often used for designing and simulating metamaterials for RF and microwave applications.
  3. Lumerical: This software offers a suite of tools for simulating electromagnetic, optical, and heat transfer phenomena, making it well-suited for designing and simulating metamaterials for various applications, particularly in photonics and optical communication.
  • asked a question related to Metamaterials
Question
3 answers
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?
Relevant answer
Answer
It slightly varies over frequency, both for the real and the imaginary part. Be careful that "FR-4" is designating a family of materials, basically they are "Flame retardant". This means that their dielectric properties are not controlled at all. I would recommend to get the datasheet of the PCB material you'll use. If it contains data at the frequency of interest, then you can be confident that the substrate will perform as expected. You can also do a measurement of the permittivity of the substrate. Some companies do offer that service.
  • asked a question related to Metamaterials
Question
4 answers
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
Relevant answer
Answer
Thanks for your response dear
Libi Mol V.A
Yes I've used this technique to get the results. But, as I mentioned i want to know why Floquet ports can't model lossy (as well as dispersive) half-space medium without using the Open add space boundary condition (BC).
Because, by considering a quarter wavelength space between the medium and Floquet port (via using Open add space BC ), we don't model a half-space anymore. Accordingly, we can obtain results approximately by considering sufficient thickness for the lossy medium.
  • asked a question related to Metamaterials
Question
6 answers
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 ???
A= 1-R-T
What is the value of R and T in terms of the S-parameter in TE and TM mode???
Values of R and T:
SZmax(1),Zmax(1), SZmax(2),Zmax(1), SZmin(1),Zmax(1)
SZmax(2),Zmax(2), SZmin(2),Zmax(2).........any other
Relevant answer
Answer
Dr. Sankari Manda
Thank you, sir, for answering my question. Although I still have doubts about the formula for metamaterial absorber absorbability in terms of the S-parameter in TE and TM modes.
A=1-R
A=1-|SZmax(1), Zmax(1)|^2-any other terms for TE and TM modes???
  • asked a question related to Metamaterials
Question
2 answers
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.
Relevant answer
Answer
The bottom layer should be thick enough that the evanescence wave is almost gone by the bottom surface. To the degree that is not possible, you do not want a fake reflection in your calculation. Set the boundary condition to absorb the remaining field.
  • asked a question related to Metamaterials
Question
1 answer
accurately, i wanna know how to design a transmissive metamaterial cell that produces a wide range of phase differences?
Relevant answer
Answer
I am not sure your question is very well posed, but to get any strong effect you need a strong wave-metamaterial coupling (eg for EM waves, some kind of electrical interaction, as per an appropriately designed metallic structure such as a split ring resonator or a fishnet). If you want a wide range of responses over a narrow bandwidth, then the structure itself will (also) have to have a similarly narrow resonance.
I suggest you first look at some of the basic literature on e.g. SRR's, or abstractions such as the Lorentz model, or the Drude model, to see how they behave and what they can do.
  • asked a question related to Metamaterials
Question
2 answers
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
Relevant answer
Answer
Basically, it is required to transform the thickness of the lens for each light ray to: first, the optical path length, and then to phase shift. And with the phase shift profile you can now design an equivalent metalens.
The fundamentals of the phase change introduced by a lens can be found in Goodman's book "Introduction to Fourier Optics".
An introduction to the optics of metalens is in "Optics of the metalens"
  • asked a question related to Metamaterials
Question
3 answers
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
Relevant answer
Answer
If you know how to plot the dispersion diagram of a unit cell, it is pretty easy to plot the dispersion diagram of a ribbon supercell. You could use the same eigenmode solver as you would do for the unit cell, it is just that you use the periodic boundary condition along one direction (the periodically repeated direction) but use other boundary conditions (e.g., PEC or scattering boundary conditions) at the two ends of the finite supercell. You then can get the dispersion diagram of a ribbon supercell by just scanning the frequencies as a function of momentum along the periodic direction.
  • asked a question related to Metamaterials
Question
4 answers
Please share reference is any one has. I am looking in terms of antenna design perspective
Relevant answer
Answer
Malcolm White I generally urge some caution on defining many of your listed products as metamaterials; strictly speaking, these devices must possess behaviors or abilities beyond those found in natural materials in order to qualify.
Simply being periodic strictly isn't sufficient, although that's what the term has degenerated into in the current literature, I suppose.
I have worked on some lower-frequency "metamaterial" applications (I would prefer to categorize them as artificial transmission lines) in the ~100 MHz range. Based on these, I think it shouldn't be too much effort to get this down to the ~1 MHz rage, but you would be working with fairly large components at this point.
  • asked a question related to Metamaterials
Question
11 answers
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.
Relevant answer
Answer
The absorptance is obtained through the equation
A(w) = 1 − T(w) − R(w), where T(w) and R(w) represent transmittance and reflectance, respectively.
Since, the perfect absorber can be discerned by reducing reflectance and transmittance to zero.
When the thickness of the bottom continuous (substrate) much than skin depth of electromagnetic waves, The transmittance can be effectively eliminated and the absorptance equation is A(w) = 1 − R(w).
  • asked a question related to Metamaterials
Question
2 answers
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 ?
Relevant answer
Answer
Go through the provided link
You can find the details about de-embedding of the ports under Distance to reference plane subsection
  • asked a question related to Metamaterials
Question
1 answer
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?
Relevant answer
Answer
Well, you might imagine designing the membrane to have the same resonant frequency as the Helmholtz resonator; but I think that I would prefer to call that (e.g.) two degenerate resonant frequencies (due to their different underlying mechanisms); rather than to call it "one resonant frequency".
  • asked a question related to Metamaterials
Question
1 answer
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.
Relevant answer
Answer
First of all, you have to mention that what kind of structure you wish to design and which materials temperature you want to vary. You may follow this article. This article is related to temperature variation.
  • asked a question related to Metamaterials
Question
4 answers
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.
Relevant answer
Answer
Thank you Pankaj Binda sir.
  • asked a question related to Metamaterials
Question
2 answers
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?
Relevant answer
Answer
Adding to what Malcolm White said, a metamaterial can also be added on top of the antenna to alter the near-field and hence achieve far-field beamforming like beam-shaping and polarization conversion.
  • asked a question related to Metamaterials
Question
3 answers
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
Relevant answer
You may use the numerical homogenisation method:
  • asked a question related to Metamaterials
Question
2 answers
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)?
Relevant answer
Answer
Dear Leon
Thank you for the feedback and for the references.
I'll read the references and post a comment.
Best regards.
Marcos
  • asked a question related to Metamaterials
Question
4 answers
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?
Relevant answer
Answer
It depends on what you are looking for, you can convert S parameters to ABCD parameters in ADS and then use the abcd parameters to get different impedance/admittances of different circuit structures such as pi/t-models.
  • asked a question related to Metamaterials
Question
16 answers
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.
Relevant answer
Hi Nidhi
This article involves all equations and m-file for extracting metamaterial characteristics, you can check your simulation and code with this:
Extraction of Material Parameters for Metamaterials Using a Full-Wave Simulator
  • asked a question related to Metamaterials
Question
2 answers
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?
Relevant answer
Answer
Hi
In this link, you can simply learn the method of extracting metamaterial parameters:
  • asked a question related to Metamaterials
Question
6 answers
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?
Relevant answer
Answer
I'm not quite familiar with phonons simulations, but it sounds like you want to display the dispersion relation of your system, right?
If so, COMSOL should return you a phonon map or something similar, but you'll need to cast that in the K-space through fourier transforms in MatLab.
  • asked a question related to Metamaterials
Question
1 answer
We want to simulate a metamaterial Antenna in HFSS.
Relevant answer
hi
you can use the below addresses for the first time and then modify your metamaterial unit cell structure for your goal:
  • asked a question related to Metamaterials
Question
6 answers
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
Relevant answer
Answer
Nitish Katiyar Thanks for your reply. I have already referred to the tutorials in the application library specifically "Acoustic Transmission Loss through Periodic Elastic Structures". In this tutorial, they assigned the wavenumber of the incident wave to the Floquet periodicity condition as well. I have based my analysis on this and I am performing a sweep over frequency but, for an x-directional incident wave the ky is getting zero as I am taking ky=k0*sin(theta). This has got me a bit confused.
Are you referring to any specific tutorial? Again, thanks for your reply :)
  • asked a question related to Metamaterials
Question
5 answers
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.
Relevant answer
Answer
Paul Kinsler Thank you sir for your last reply.
This form will be union.
I have one more question . I want to calculate the transmission loss through a structure having a membrane and cavity and supported by an acrylic plate.
I am simulating using comsol multiphysics.
Over membrane I have chosen solid mechanics. The air cavity is assigned pressure acoustics but what about that backing acrylic plate.
I have to assign it as pressure acoustics or solid mechanics.
  • asked a question related to Metamaterials
Question
3 answers
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?
Relevant answer
Answer
There are virtual particles in vacuum space that we haven't discovered yet experimentally. But this theory proves their existence:
I could verify the existence of detected and hidden particles using teaching about ultimate realities in Abhidhamma.
There is a similarity between the elementary particles (dimensional sets) and Material Forms (Rūpa) mentioned in Abhidhamma.
According to Abhidhamma, there are 28 material forms:
Concretely Produced (Nipphanna)
I. Great Elements (Mahā Bhūta):
1. Pathavi (Extension/Hardness)
2. Apo (Cohesion/Fluidity)
3. Tejo (Heat/Hotness)
4. Vāyo (Motion/Pushing & Supporting)
The above 4 great (Mahā) elements are not the emerged/derived elements. And those four elements made the following 24 elements:
II. Internal (Pasāda) Rupa:
5. Cakkhu (eye element) ==== Photon?
6. Sota (ear element) ==== Z Boson?
7. Ghāna (nose element) ==== W Boson (1)?
8. Jivhā (tongue element) ==== W Boson (2)?
9. Kāya (body element) ==== Gluon?
III. Gocara (Objective) Rupa:
10. Vaṇṇa (visible) ==== Electron?
11. Sadda (Sound) ==== Up Quark?
12. Gandha (Smell) ==== Down Quark (1)?
13. Rasa (Taste) ==== Down Quark (2)?
* Phoṭṭhabba (Tangibility, warmth, and movement) comes
from 3 mahā bhuta of pathavi, tejo, vāyo
IV. Bhava Rupa:
14. Itthi (Feminine) ==== Neutrino (1)?
15. Purisa (Masculine) ==== Neutrino (2)?
V. Hadaya (Mind Base):
16. Hadaya Vatthu (seat of the mind) ==== Z (1/2)?
VI. Life:
17. jīvitindriya (Life faculty) ==== Higgs Boson?
VII. Nutritional:
18. Oja (Nutriment) ==== Magnetic Monopole?
Abstract (Anipphanna) Rupa
VIII. Limiting Phenomenon:
19. Ākāsa dhātu (space element)
IX. Communicating (Viññatti) Rupa:
20. Kāya Viññatti ==== AXion (A)?
21. Vaci Viññatti ==== AXion (X)?
X. Mutable (Vikāra) Rupa:
22. Lahutā (lightness)
23. Mudutā (Elasticity)
24. Kammaññatā (weildiness)
XI. Material Qualities (Lakkhana Rupa):
25. Upacaya (production)
26. Santati (continuity)
27. Jaratā (Decay)
28. Aniccatā (Dissolving)
There is a mathematical way to derive the detected elementary particles and the hidden particles. Please consider reading my book on Binary Mathematical Physics and Buddhism to learn more about dimensional sets.
  • asked a question related to Metamaterials
Question
1 answer
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.
Relevant answer
Answer
Hi there,
HFSS is a complete 3D electromagnetic solver, so the direct result is a vector EM field inside your model volume. There is an internal field calculator where you can define the expression you need (for example, ScalarY(Vector_E) ) and perform basic math operations on points, lines, planes, or subvolumes. Basically, if you know the definition of your "ratio", you can calculate it from scratch.
Regards,
Andrei
  • asked a question related to Metamaterials
Question
5 answers
which is efficient model to generate band gaps for acoustic meta materials
Relevant answer
Answer
The following RG link is also very useful:
  • asked a question related to Metamaterials
Question
5 answers
Hi all,
Looking at the wikipedia page for photonic crystals, there is a section that reads:
"One-dimensional photonic crystals can include layers of non-linear optical materials in which the non-linear behaviour is accentuated due to field enhancement at wavelengths near a so-called degenerate band edge. This field enhancement (in terms of intensity) can reach N^2 where N is the total number of layers"
Can anybody explain this effect? Is there a field enhancement if a 1D photonic crystal is made of two materials with arbitrary permittivities, eps1 and eps2?
Does the enhancement happen without the non-linear permittivity? All materials will exhibit some natural non-linearity, if you drive them hard enough, right?
Or is the magic due to something with this 'degenerate band edge'? Can someone expand on degenerate band edge?
Relevant answer
Answer
This is not so mysterious. This is an interference phenomenon. The easiest illustration is probably an etalon. Suppose you have an etalon where each surface has 50% transmission. A beam with intensity I is incident. In the first pass through the material the intensity is I/2. Half of that reflects at the second surface and bounces back to the first surface. There half of that bounces again and continues in the original direction. The intensity of this second pass is I/8. Each subsequent pass is 4X smaller. So, the whole sequence is
I/2 + I/8 + I/32 + etc. However, remember that the field strength is the square root of the intensity. So, the fields add up as sqrt(1/2) + sqrt(1/8) + sqrt(1/32) etc. Adding up those first three terms, you see that the electric field is now up to 1.23! So, if you have a nonlinear phenomenon which is proportional to E^2 or higher, you actually can get enhancement in some parts of the interference pattern. In the case of the etalon the place where you get the enhancement is only inside the etalon. As for being at a degenerate band edge, they are talking about the places where the waves interfere constructively. In the example of an etalon, this happens only if the etalon is the right thickness: t = N * lambda/(2*n) where n is the index of refraction. It's a degenerate band edge in that you can see the behavior repeats at any integer multiple lambda/2. All those choices are degenerate, i.e., do the same thing, and in between you have a repeating range of behaviors (a band) that culminates at the places where the behavior starts over (the edge of the band)
This sort of behavior is very common in all sorts of interference phenomena. Different paths add up in constructive interference and you get a crest with amplitude higher than the contributing pieces. The enhancement isn't magic in that the enhancement comes from adding up pieces that come from somewhere. In the case of the etalon you are adding up parts of the beam that are distinct in time. In other constructive interference you might be adding up pieces of the incoming beam that were distinct in space and laying them over each other. Every bright spot comes with a similarly dark spot because you can't get something for nothing. However, in the case of non-linear optics where you care about the field strength rather than the intensity, clever design can produce dramatic enhancement.
  • asked a question related to Metamaterials
Question
7 answers
Hi,
I am trying to plot the dispersion diagram for a transmission line metamaterial IFA antenna, consisting of a capacitor in series and an inductor in parallel to the antenna.
As far as I know, the dispersion diagram is the plot of frequency vs. phase of S21, as phase (theta) is beta*length.
But how to plot the dispersion diagram of an antenna which has only one port?
Kindly help me!
With Regards,
Suhas D
Relevant answer
Answer
Thank you Madam Aparna Sathya Murthy and Sir Stuart Barth for your help.
I was going through a paper titled "Small Antennas Based on CRLH Structures: Concept, Design, and Applications."
In this paper the authors have come up with the dispersion diagram of a 3 cell metamaterial antenna (please find attached the image). But I don't understand how they got it. This is the kind of dispersion diagram I need for my metamaterial IFA antenna to observe the Right Handed and Left Handed regions.
Any ideas? Please do help!
With Regards,
Suhas D
  • asked a question related to Metamaterials
Question
3 answers
I have a metamaterial absorber structure consisting of several metal-dielectric-metal layers, I have drawn the electric and magnetic field distribution between every two layers.
I want to get the value of the electric and magnetic fields, to calculate the amount of power entering each layer. Note that I am using the Lumerical program (FDTD).
Is there a code or a script for an E, H, and power calculation?
Thanks.
Relevant answer
Answer
Farooq Abdulghafoor Khaleel, thank you.
  • asked a question related to Metamaterials
Question
7 answers
I plotted the field strengths of the metamaterial absorber layers, and these values are shown to me on the right of the figure. What do these values represent? If it represents the strength of the field, isn't this value too large?
The values that are shown on the right of the graph, what represent?
what do you mean? What is its unit?
Relevant answer
Answer
Saad Zahraw Sekhi You are welcome
  • asked a question related to Metamaterials
Question
3 answers
I can not extract the material properties of a structure from the CST studio suite. Whenever I set the effective thickness of the material to the Substrate thickness, I get a template-based post-processing error (See the attached Screenshot). What is the reason for it? What does it mean by "effective thickness of the material"? Does it mean the substrate thickness? Please help me extract the material properties with CST. Any suggestions will be gladly appreciated.
Relevant answer
Answer
The thickness of the material that I have used is 55nm Ahmed Jamal Abdullah Al-Gburi
  • asked a question related to Metamaterials
Question
7 answers
Metamaterials can have exotic material properties. I have come across some metamaterial papers in which the effective permeability or permittivity can be negative. Is it possible to possess positive effective permeability or permittivity by any metamaterial design?
Relevant answer
This answer is copied from the wikipedia:https://en.wikipedia.org/wiki/Metamaterial,
Double positive medium[edit]
Double positive mediums (DPS) do occur in nature, such as naturally occurring dielectrics. Permittivity and magnetic permeability are both positive and wave propagation is in the forward direction. Artificial materials have been fabricated which combine DPS, ENG and MNG properties.[3][16]
To get ref. 3 and 16 refer to the link.
Best wishes
  • asked a question related to Metamaterials
Question
12 answers
How to design and analyse metamaterial unit cell...
Relevant answer
Answer
Vivek Prakash Yadav i do feel that the Design and Analysis of Two Novel Metamaterial Unit Cell for Antenna Engineering needs to be looked at and the link I have shared here with gives u a perfect picture about the same and hope this is useful to you
One more similar paper publication I came across ResearchGate related to Evaluation of metamaterial unit cell analysis techniques and this is in line with your query as well
  • asked a question related to Metamaterials
Question
4 answers
to design antenna with metamaterial
Relevant answer
Answer
you can use Lumerical software simulation (FDTD) too.
  • asked a question related to Metamaterials
Question
3 answers
i am doing work in acoustic metamaterial and i have no idea how to do simulation . thats why i want to know simulation of a sonic crystal in brifely
Relevant answer
Answer
you can see the following link:
  • asked a question related to Metamaterials
Question
3 answers
Hello all,
I am working on metramaterial these days,, and I got confused about Negative phase velocity and positive group velocity in metamaterials. I know how to obtain the equations but I can't understand how a wave can have Negative phase velocity (the direction of the wave), but the power propagates in the opposite direction. How would it be possible?
Relevant answer
Answer
You better read:
V.G. Veselago. ‘‘The electrodynamics of Substances with Simultaneously Negative Values of Img Align= Absmiddle Alt= ϵ Eps/Img and μ.’’ Physics-Uspekhi, vol. 10, pp. 509-514, 1968.
  • asked a question related to Metamaterials
Question
7 answers
There are so many papers where they select different materials for forming metamaterial also use different substrates as well as liquids that evaporate. What interests me most is which materials show the best result to form metamaterials that can be used for nanoantennas. Thus I want to know what to select for forming metamaterials.
  • asked a question related to Metamaterials
Question
2 answers
I found on comsol database one online webinar/workshop where a terahertz metamaterial was modeled and there, input "(px*py/4/2/Z0_const)*E0^2" this equation is used. I need to know why is this used?
Relevant answer
  • asked a question related to Metamaterials
Question
8 answers
There are so many papers where they select different methods for forming metamaterial. In some papers, they used AC sources in others DNA origami and so on. What interests me most is which exact equations show the result to form metamaterials. Thus I want to know what to select for forming metamaterials.
Relevant answer
Answer
Fatematuz Zahura are you referring to the physical properties of the metamaterial (e.g., its shape), or the modal properties of the metamaterial (e.g., its dispersion)? While the two are related, generally one of these two is chosen to begin the design with.
Possibly the most simple are transmission-line metamaterials (https://www.waves.utoronto.ca/prof/gelefth/Eleftheriades_Materials_Today_March2009.pdf) -- which can produce very exacting equations -- but are of course simply modelled and are fundamentally just abstractions of physical systems.
On the other hand, complex structures such as your DNA origami can be simulated to a high degree of accuracy, but because they are so complex, it is virtually impossible to find any generalized expression for their behavior.
Somewhere in between is a region where approximate expressions produce reasonably accurate modal results for generalized structures. For example, regular defects made in any material will tend to suppress the propagation of energy when the wavelength of the energy is around one-quarter wavelength in the material.
Selection, I think, should really start with the specifics of your application.
  • asked a question related to Metamaterials
Question
6 answers
Any reflective surface of the dielectric material increases the gain of patch antenna, but when metamaterial is used as a superstrate layer on the patch antenna why the gain is improved more? What is the difference between any reflective surface and metasurface in the case of patch antenna?
Relevant answer
Answer
A metamaterial is not just, or perhaps not even, a reflective surface. It can have lots of special properties, like having equal phase across its surface, which would increase gain considerably.
  • asked a question related to Metamaterials
Question
3 answers
In the comsol simulation of the elastic wave metasurface, what module is used? How is the incident field of a periodic unit set (boundary load/specified displacement)?
And for example, when the longitudinal wave is incident, how to integrate the amplitude (p0, p1, p-1, s0, s1, s-1) of each diffraction order of the longitudinal wave/transverse wave?
Relevant answer
Answer
There are two different modules you can use to simulate the propagation of the elastic waves:
1- Acoustic module > elastic wave.
2- Structural mechanics.
However, the solution output of these two modules is not totally the same. for instance, if you want to calculate the acceleration then you have to use the Structural mechanic module as this value is not available in the Acoustic module.
  • asked a question related to Metamaterials
Question
6 answers
Greetings to everyone,
Can anyone please tell me which parameters settings are used in a simulation of metamaterial and metasurface unit cells in CST? (Background, boundaries, global properties, etc. )
Relevant answer
Answer
Please check this reference
It provides a MATLAB code to extract the permeability and permittivity plots from S-parameters.
  • asked a question related to Metamaterials
Question
1 answer
for a Perfect metamaterial absorber how we can find Absorptivity with different angles of ring rotations in HFSS software?
Relevant answer
Answer
I assume you're running a two-port Floquet simulation of the unit cell. You can find the relative power lost/absorbed from the S-parameters as follows:
relative power lost/absorbed = 1- |S11|^2 - |S21|^2
  • asked a question related to Metamaterials
Question
9 answers
I want to simulate this using the Acoustic structure interaction module.
For ease this can be done by taking a single unit.
How can I do this in comsol?
Relevant answer
Answer
Dear Nitish Katiyar
I suggest "scatterer on substrate" mph file availbe both in COMSOL website and applican builder within the software.
  • asked a question related to Metamaterials
Question
5 answers
Is there any open source code (C, C++, Python or Matlab) for discrete dipole approximation for scattering problems in a complex dielectric medium ?
Relevant answer
Answer
Indeed, if you have a complicated environment around a finite particle, than your best choice is a direct discretization of a large chunk of this environment (with any DDA code, like DDSCAT or ADDA).
The only available option to avoid this is for a semi-infinite substrate - ADDA can account for it analytically (discretizing only the scatterer itself). See https://github.com/adda-team/adda and the paper
  • asked a question related to Metamaterials
Question
2 answers
I am looking for the latest approaches to find the band-gap of Phononic / Periodic materials. In this regard, if anyone knows a reference (in detail) for Finite Difference Time Domain (FDTD) theory along with the Bloch method, please share.
I really appreciate any help you can provide.
Relevant answer
Answer
For arbitrary unit cells, your best bet is an eigenmode simulation. Sweep the Bloch phase shifts across the various axes from 0 to pi and solve for the eigenfrequencies. The regions in which there are no found eigenfrequencies are your band gaps.
  • asked a question related to Metamaterials
Question
6 answers
Does the wavelength the unique criteria to choose the size of unit cells in metamaterial regime ? particularly for microwave applications.
Relevant answer
Answer
Instead of asking the physical dimension, it would be more accurate to know the electrical length of the unit cell. We have to use the trial error method always for a certain limiting error. For example, if Lamda/10 does not give correct results in FDM or FDTD, etc numerical technique, we refine the mesh. if we het the results within lamda/5 meshing, we use it.
The length (electrical) of the unit cell depends on the area on application.
1. if you are using within metallic waveguide, much smaller than the conventional substrate based metamaterial. The final results depend on the bending of electric/magnetic fields and its total length (electric/magnetic).
2. Similarly, we are designing a metamaterial using a substrate, please, use the trial error method to generate a suitable electric length to achieve your results. With my limited knowledge, it is found from the published research articles, if we are working upto 18 or 20 GHz, the physical dimensions of the unit cell is approximately 7-10mm depending on application. Form example, at 18GHz, lamda = 16.67mm. Lamda / 4 = 4.17mm.
But, the physical dimension is 7.5mm X 7.5mm or 10mm X 10mm.
  • asked a question related to Metamaterials
Question
4 answers
I have designed an antenna whose gain I want to increase,pls suggest how to see which metamaterial will fit in
Relevant answer
Answer
Usually the resonant frequency of the metamaterial unit cell is selected same as that of patch antenna. However it must consider the parameters like pass band, stop band, miniaturization factor etc. For gain enhancement applications you can use High Impedance Surfaces. Software optimization also helps to arrive at optimum dimensions.
  • asked a question related to Metamaterials
Question
3 answers
I see professional advice to help to attenuate a highly directional interference.
We have a large (~3m) satellite dish antenna for collecting earth observation data. This antenna rotates to scan the sky and works in an 8 GHz band. Unfortunately, a point to point wireless link interferes with the reception during certain hours, and we cannot shut them down due to difficult legal processes.
We have built a metallic wire mesh screen, but it seems to have only a low effect (maybe because of mesh cell size or overall size ... but we are unfortunately limited due to the wind load).
We are considering using frequency selecting structures (FSS) or metamaterials/metasurface to create "negative gain" and thus attenuate the waves coming from the specific direction of the interferer.
Would you mind suggesting some good references to assist with designing such a low-wind-load structure, or perhaps better ideas?
With thanks,
Albert Lysko
Relevant answer
Answer
Dear Colleague,
hope this will help
  • asked a question related to Metamaterials
Question
6 answers
Dear all,
I recently meet a problem when I use RCWA codes.
In the same structure, it tooks fewer time when using the FDTD solution.
I need set a lot of orders to calcuate the structure which can reach the similar result.
So I have a question that how can I judge the accuracy of the simulation when I use RCWA codes? and How to judge the orders I need?
Thanks
Relevant answer
Answer
Sai Chen I am writing the code with matalb, base on Rumpf's lecture. first step. I just consider the normal insert. But very bad news, I the calculate the inverse matrix, no matter inv, ^(-1), pinv,it can not give the right results. And when the harmonics become large (such 40), it give a lot of warning, It seem it is the problem of calculate the inverse matrix. Thank you, do you know why? And the code I write is very short. Less than 200 lines.
  • asked a question related to Metamaterials
Question
3 answers
I am trying to simulate THz metamaterials in CST Microwave studio where the transmission needs to be studied with varied amplitude of the excitation signal and the field confinement in my structure in each case. Would highly appreciate your suggestions on this...
TIA.
Relevant answer
Answer
I don't know how to do it. This white paper from CST indicates that it is possible. Probably there is more available on the web and in the help.
  • asked a question related to Metamaterials
Question
2 answers
I am currently trying to simulate a THz metastructure in CST studio using the frequency domain solver. I would like to know if it possible to change the field strength of the incident radiation. TIA.
Relevant answer
Answer
Jihong Zhang Thank you for the answer.The material I am trying to simulate is non-linear in nature, the optical constants are strongly dependent on the field. Which is why I want to alter the excitation strength. I found out that one can feed a custom input signal from the new signal tab under the simulation tab.
  • asked a question related to Metamaterials
Question
3 answers
1. How to assign waveport when top conductive pattern (patch) is smaller than the substrate size? Any reference from where the details can be seen ?
2. Master/slave boundary and waveport excitation are not compatible either in this scenario. Without assigning master/slave boundary conditions, can we get accurate dispersion diagram?
3. Unit cell analysis of a linear array (extending only in one dimension) is required. I have found "Unit cell analysis of a Two-D array (for instance, EBG structure)" but in that case port assignment is a totally different scenario.
I don't want to assign Floquet Port on top/bottom of the air box.
Unable to understand the slide number 3 mentioned in the picture.
Thanks for any help!
Relevant answer
You can use the boundary condition (BC). However, your EBG unit cell connected with Vias or not?
  • asked a question related to Metamaterials
Question
3 answers
Greetings to all!
How does metamaterial affect antenna Gain and Bandwidth? What are the physics behind them.
Relevant answer
Answer
A resonant antenna is a resonant circuit, a metamaterial is also a resonant circuit. Coupled resonant circuits can have useful properties, like increased bandwidth. Look up coupled resonators, double tuned filters, for instance.
Some of the radiation from a patch, for instance, is from the ground. Metamaterials radiate differently to a conducting ground, and can give increased gain in some directions, by reducing radiation parallel to the ground, for instance, or increasing the radiating aperture.
  • asked a question related to Metamaterials
Question
14 answers
I have designed a split ring resonator with a metal ground so my S21 is zero. How can I plot the permittivity and permeability and impedance in HFSS?
Since I have used metal ground I also can't find the phase of S21.
Relevant answer
Answer
See this article
INVESTIGATION OF EFFECTIVE PERMITTIVITY AND PERMEABILITY FOR A NOVEL V-SHAPED METAMATERIAL USING SIMULATED S-PARAMETERS
  • asked a question related to Metamaterials
Question
13 answers
Hi,
I'm trying to simulate a split ring metamaterial from this paper ' - μ Compact magnetic metamaterial lens for 0.35-T MRI' by Hassan Ali et al 2017 in CST Microwave Studio but I'm unable to achieve any resonance in the expected frequency of around 14.88 MHz. I'm unable to get any resonant behaviour in the megahertz range at all. Could anyone check to see if I'm setting up my simulation correctly?
Relevant answer
Answer
Great
  • asked a question related to Metamaterials
Question
6 answers
Hi Community!
I want a detailed answer or document in which I got to know how you can design a unit cell of metamaterial for a particular frequency and how to bring periodicity to the structure. I have searched a lot but couldn't find an appropriate answer. If someone has the document related to it or had experience in it then kindly help me out.
Thank you!
  • asked a question related to Metamaterials
Question
2 answers
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?
Relevant answer
Answer
Yes it has normalized impedance, but i want to know how can i get this normalized impedance in CST.
  • asked a question related to Metamaterials
Question
6 answers
If in the antenna design only one SRR structure is used, so can it be also called as Metamaterial based antenna, any literature suggestions for such type of antenna structures.
Relevant answer
Answer
A transmission line can be made from a network of series inductors and shunt capacitors. Calling one SSR structure a metamaterial is like calling one inductor and one capacitor a transmission line.
  • asked a question related to Metamaterials
Question
2 answers
Dear Sir/ ma'am
When I am doing a simulation of a unit cell of metamaterial in CST, I am getting a warning "mesh adaption termination because of maximum passes is reached". What is it and how much it affects the simulation and to avoid it. I reduced the frequency range from 4 GHz to 1GHz but still, I am getting the same warning. Below I have attached the image of the warning.
Relevant answer
Answer
Thank you, Sir, for your valuable suggestion. Can you tell, how to avoid it or solve it?
  • asked a question related to Metamaterials
Question
3 answers
What's the application of metamaterial with respect to acoustic propagation in engineering?
Relevant answer
Answer
Dear Yunya Liu in addition to Masoud Mohammadi I would like to add that you can use metamaterials for changing the flow of sound, for instance to change the direction of propagation of the acustic wave, furthermore you can use metamaterials for basically the same kind of operations that with ligh, expliting the beam, wavefront shaping etc.
Hope it helps.
  • asked a question related to Metamaterials
Question
6 answers
My design contains three parts.
A silicon rubber membrane is placed between upper and lower part.
I want to calculate sound transmission loss by using comsol Multiphysic.
There are lots of module inside Acoustic section.
Which module will be suitable for this??
Relevant answer
Answer
Please consider this publication: An analytical model for broadband sound transmission loss of a finite single leaf wall using a metamaterial: DOI: 10.1121/10.0000923. The main model is there is analytical, but verifications is done with COMSOL.
  • asked a question related to Metamaterials
Question
3 answers
Hello Dear Researchers,
Is there any guidelines or mathematical formulas (or any reference) on how to calculate the dimensions of the unit cell for metamaterials, metasurfaces or Artificial Magnetic Conductor applied to Antennas or Filters ?
Thank you in advance for your assistance...
Relevant answer
Answer
You can probably make the cells a little bigger than 0.1 wavelength, depending on the type of cells and application, but Vadym Slyusar is basically right. It is similar to mesh rules for electromagnetic modelling, you are replacing smooth space with discrete lumped space.
  • asked a question related to Metamaterials
Question
2 answers
I designed a 3x3 metamaterial resonating at 28GHz, the return loss is fine but the gain is negative. How can I improve it and also are there any applications of negative gain?
Relevant answer
Answer
Can I assume you that your metamaterial was powered/active, and were hoping that it would actually have gain? If so, then I suppose interesting questions would be (a) how much of the natural loss of an unpowered version have you alleviated, and (b) how controllable is that loss compensation?
There is a lot of work on PT symmetric metamaterials, comprising two (or more) segments which have losses in one part, carefully matched with gain in the other. Perhaps even if your unsuccessful attempt at generating gain cannot be improved on, a variable loss version might possibly still have some utility; although this seems to me to be most likely be a rather optimistic view.