Thesis on metamaterials

Throughout the thesis, we consider the initial plane electromagnetic wave that is normally incident to the flat boundaries of the chain.

Electromagnetic interactions in one-dimensional metamaterials

The wave has the magnetic induction vector parallel to the axes of rods while the electric intensity vector is perpendicular to the ones. The above effective complex dielectric and magnetic constants have been obtained for the first time by author of the thesis on base of extension of the case of 2-D infinite metamaterial medium to a slab metamaterial scatterer under consideration through the implementation of the Effective Medium Theory EMT in appropriate frequency range.

The expressions of the appropriate effective constants for the infinite medium are obtained by other authors. These expressions of the effective constants obtained in this thesis takes in account multipole effects for the case of composite with a very small value of the rods volume fraction while dipole effects are taken in account for the case of large volume fraction values.

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  • Manipulating Wave Propagation Using Architected Metamaterials.
  • metamaterials.

The accuracy of obtained mathematical models was always benchmarked through a comparison with numerical calculations obtained via the implementations of Finite-Domain Time-Difference FDTD method for calculating S-parameters of a metamaterial structure under considerations. S-parameters were used to calculate the effective constants by means of the using Nicolson-Ross approach.

All of the numerical experiments presented in the thesis have been carried out with the help of the free Meep FDTD software package while analytical modeling has been done using MatLab software. In this thesis, an improved broadband method for determining complex effective refractive index, dielectric and magnetic constants of an arbitrary passive metamaterial has been proposed.

how to design metasurface and metamaterial in cst microwave studio

Evaluation of the effective parameters is realized using the reflection-transmission S-parameters obtained by simulation or experimental measurements and analytically evaluated interface reflection coefficient of the slab. The effective electromagnetic properties of infinite 2-D array of copper cylinders immersed in metal-dielectric matrix in the GHz frequencies shows the existence of the enhancement of effective dielectric constant and low absorption in the microwave frequencies.

The obtained analytical models of the composite in the thesis gives a good qualitative but a weak quantitative correlation with results of numerical simulations in the case if cylinders touch each other.

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The above analytical models of infinite metamaterial medium quantitatively describes well the slabs embedded with the above metamaterial medium if there is some relation between the width of slabs and the dimension of unit cell of the metamaterial medium for appropriate frequency range. The considered artificial material medium can be used to increase the directivity of patch antenna and to obtain ULI structures in the GHz frequency range and to design a new type of waveguides. The main theoretical results of this thesis can be presented by two theoretical methods of characterizing of any 2-D slab metamaterial structures in the microwave frequencies via EMT approach: 1.

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  • Manipulating Wave Propagation Using Architected Metamaterials.
  • Electromagnetic interactions in one-dimensional metamaterials;

In this regard, lattice materials with different coordinate numbers are more efficient. Here, a group of hierarchical honeycombs was introduced. The introduction of a structural hierarchy into regular honeycombs gives rise to broad and multiple phononic band gaps. Importantly, an inversely proportional relation between relative density and band gap size was observed. As a result, lightweight yet stiff metamaterials can be designed for vibration mitigation.

The optical properties of metamaterials

The rest of this thesis will focus on the mechanical tunability of vibration mitigation in a new group of stretchable lattice metamaterials. The proposed lattice metamaterials exhibit broadband vibration mitigation capability, which can be dynamically tuned by an external mechanical stimulus. Experimental studies were also conducted to validate the numerical simulations.

The findings presented here will open new avenues to control noise and vibration using architected metamaterial systems.

Properties and applications of lossy metamaterials

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  • Advances in microwave metamaterials.
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  • abstract of dissertation proposal;
  • Manipulating Wave Propagation Using Architected Metamaterials;