Unique Retrieval of Complex Permittivity and Permeability of Dispersive Materials From Reflection and Transmitted Fields by Enforcing Causality

Varadan, Vasundara V.; Ro, Ruyen

doi:10.1109/tmtt.2007.906473

Cited by 125 publications

(70 citation statements)

References 19 publications

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“…After the scattering parameters of the structure in Fig. 12 are solved by using the mode matching method presented above, the effective μ and can be retrieved by using the approach in [29]. It is true that the periodic unit of the microstrip line metamaterial absorber, especially the nonuniform microstrip line metamaterial absorber, may not be much smaller than the wavelength of the upper frequency in the waveband of interest.…”

Section: Effective Permeability and Permittivity Of The Metamaterials mentioning

confidence: 99%

“…Suppose the reflection coefficient is ρ 0 in the waveband from λ min to λ max . From (29), the following inequality can be obtained [33]:…”

Section: Ultimate Bandwidth Limit Of the Metamaterials Absorbermentioning

confidence: 99%

“…From either (29) or (32), it can be seen that with increasing static permeability and thickness of the substrate, the bandwidth limit of the metamaterial absorber increases. However, it has to be mentioned that when (30) is derived, the reflection coefficients in the absorption waveband are assumed to be exactly the required absorption limit [33].…”

Section: Ultimate Bandwidth Limit Of the Metamaterials Absorbermentioning

confidence: 99%

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Analysis and Design of an Ultra-Thin Metamaterial Absorber

Huang¹,

Li²,

Kong³

et al. 2009

PIER B

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Abstract-This paper presents a class of ultra-thin metamaterial absorbers, which consists of periodic microstrip lines on top of a planar lossy substrate backed by a conducting metallic plate. A highly efficient full-wave analysis method was developed to solve the electromagnetic response of the absorbers. The influence of electromagnetic properties of the substrate and physical dimensions of the microstrip lines were analyzed. Genetic algorithm was used to optimize the absorption bandwidth of the absorbers. Effective permeability and permittivity of the absorbers were retrieved to shed a new light on the absorption mechanism of the absorbers and to explain their ultimate bandwidth limit. It was found that the ultimate bandwidth limit of the metamaterial absorbers is the same as that of normal absorbers.

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Section: Effective Permeability and Permittivity Of The Metamaterials mentioning

confidence: 99%

“…Suppose the reflection coefficient is ρ 0 in the waveband from λ min to λ max . From (29), the following inequality can be obtained [33]:…”

Section: Ultimate Bandwidth Limit Of the Metamaterials Absorbermentioning

confidence: 99%

Section: Ultimate Bandwidth Limit Of the Metamaterials Absorbermentioning

confidence: 99%

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Analysis and Design of an Ultra-Thin Metamaterial Absorber

Huang¹,

Li²,

Kong³

et al. 2009

PIER B

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“…This technique is widely used for investigation of the complex dielectric permittivity of nonmagnetic materials [23], [75]. It is also used for calculation of the refractive wave index for a variety of materials.…”

Section: Kramers-kronig Extraction Techniquesmentioning

confidence: 99%

“…Based on literature, [69], [75], the phase factor may become dispersive (β) for several reasons; discontinuous phase change which exceeds 2π, choosing highly dispersive materials, considering thick samples or having a large difference between phase delay and group delay. The ambiguity can be eliminated by choosing the correct phase log count ranges between π ≤ βd ≤ 3π, where β apprehend the several phase factors range from m = -1 to +3.…”

Section: The Modification Of Nicholson-ross-weir Techniquementioning

confidence: 99%

Synthesis and Analysis of Metamaterial Structure for Microwave Frequency Applications

Uddin¹

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produce uncertainty, therefore, most of the conventional extraction technique rely on relatively thin materials. In the thick materials, the ambiguity appears in different frequency points in several branches which produces phase error. Thus, it is essential to check the proper branch that minimizes the ambiguity and this remains under explored. This doctoral research aims to fill this gap in the scholarly literature by developing a unique extraction technique that will support reducing the ambiguity error and is able to provide accurate values for electromagnetic properties. To achieve this aim, the initial research concentrated on the Nicholsonross-weir (NRW) technique. The modified NRW technique is then applied to a long-length Drude material with known parameters for validation. Another extraction technique known as Kramers-Kronig (KK) technique is also investigated. This KK extraction technique is applied to the use of Cauchy residue integrals instead of using trapezoidal rule integration. Further investigations involved experimentation by using the proposed NRW extraction technique to provide empirical evidence, such as designing a periodic dual-star split ring Synthesis and analysis of metamaterial structure for microwave frequency applications iii resonator (DSSRR) and microwave absorber. DSSRR is an electromagnetic band gap (EBG) based metamaterial structure. The proposed DSSRR structure may be implemented with an equivalent transmission line structure. The advantage of the transmission line structure is that it realizes the artificial structure with minimum losses and produce wide bandwidth. The DSSRR structure is implemented on single unit cells and multiple unit cells. The proposed DSSRR structure delivers a wide-band performance from 7.5 GHz to 9.5 GHz and a maximum rejection up to 47 dB, which offer a sharp cut-off in the reject band. The dispersion diagram exhibits unusual characteristics in both balanced and unbalanced conditions. A microwave absorber was also developed. The proposed design offers three unique shapes without using any additional resistive sheets on top of the ground plane.The three unique shapes are octagonal ring, (OR), cross-wires (CWs), and cut-off circle (CC). The proposed shapes are insensitive to polarization angle, and can achieve perfect absorption. Further work involves the successful extraction of electromagnetic properties using the NRW technique. The numerical and experimental results agree with each other, which further confirms the metamaterial behaviour.iv Synthesis and analysis of metamaterial structure for microwave frequency applications

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