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We demonstrate metamaterial-based electro-absorption THz modulators employing frequency-selective-surfaces (FSS) and graphene. By placing the graphene layer at an optimal distance from the FSS, the sensitivity of THz transmittance can be greatly enhanced.
Metamaterials represent a type of artificial electromagnetic materials and/or structures of unique electromagnetic characteristics that cannot be observed in nature materials. These characteristics, such as negative refraction, negative group velocity, band gaps and so on, hold good promise in practical applications. Metamaterial research still fails, however, to reshape the microwave industry due...
From applications of high-impedance surfaces, TM surface wave pass-band below TM band-gap was found, and for periodic artificial surfaces without a band-gap, a similar phenomenon can be found below the leaky-wave band, which form the primary discovered special features in the present research work. A novel type of surface-wave antenna based on artificial surface was built, the antenna, which has wide-band...
Arbitrary two dimensional irregular polygonal cloaks are proposed and designed basing on the coordinate transformation theory. First, the general expressions of constitutive tensors of the cloaks are derived, then there are some full-wave simulations of the cloaks that are composed of inhomogeneous and anisotropic metamaterials, which will bend incoming electromagnetic waves and guide them to propagate...
A novel rectangular patch antenna was specifically designed using planar-patterned metamaterial concepts. The patterned metal patch and finite ground plane form a coupled capacitive-inductive (C-L) circuit of negative index metamaterial. For the wideband, high efficiency, low loss and low VSWR, the novel type of antenna is used to design meta array, the array still have bandwidth significantly broadened...
Arbitrary three dimensional axiolitic cloaks are proposed and designed based on the coordinate transformation theory. First, the general expressions of constitutive tensors of the three dimensional axiolitic cloaks are derived, then there are some full-wave simulations of the cloaks that are composed of inhomogeneous and anisotropic metamaterials, which will bend incoming electromagnetic waves and...
In this paper, we have investigated the near field and far field properties of the cylindrical cloak. The total fields are analyzed in detail with the constitutive parameters as tensors, which are defined through Pendry's model. Through the numerical examples we can see that "invisibility" can be basically realized. The result is valid, and it can be concluded that such cloaking can be realized...
The paper is split into two major parts: (1) the first is to look into the EM wave properties in metamaterials and to develop an efficient solvers for their designs; and (2) the second is to try to design the metamaterials for antenna applications. For the efficient algorithms developed, the integral equation solvers accelerated using the adaptive integral (equation) method (AIM) and also the pre-corrected...
Arbitrary N-sided regular polygonal cylindrical cloaks are proposed and designed basing on the coordinate transformation theory. First, the general expressions of constitutive tensors of the N-sided regular polygonal cylindrical cloaks are derived, then there are some full-wave simulations of the cloaks that are composed of inhomogeneous and anisotropic metamaterials, which will bend incoming electromagnetic...
In this paper discussed the interaction of the plane wave with the cylindrical metamaterial cloak. The total fields are analyzed in detail, and analytical expression of the field inside the cloak has been demonstrated. The result is valid, and is helpful for the analysis and design of the cylindrically cloak, meanwhile the comprehension of the physical mechanism in cloaking.
In this letter, a further miniaturization approach for the exiting MCR design extending analysis to 3D isotropic case. It is shown that the subwavelength resonance occurs when transversal permeability components have opposite signs. In this case, the rectangular cavity supports subwavelength resonance, and the width and length of such the rectangular cavity resonator can be in principle simultaneously...
This work concentrated on an ELS (electric line source) radiating parallel to a lossy metamaterial covered infinitely long dielectric cylinder. First, the model configuration is given. Second, under different electromagnetic parameters, the patterns of the near field are given; the directivity and the normalized radiation resistance are presented to discuss the properties of the far field. During...
A rectangular waveguide filled with uniaxial metamaterial is investigated in this presentation. The EM fields distribution of TE modes in such a rectangular waveguide are derived, and transmission characteristics are discussed. It is shown that the longitudinal component of the metamaterial permittivity tensor has strong influence on the direction of the phase velocity for TE mode waves. Particularly,...
The electromagnetic characteristics of the model with an electric line source radiating parallel to a lossless inhomogeneous and anisotropic metamaterial covered infinitely long conductor circular cylinder is investigated in this paper. First, the permittivity and permeability tensors of the metamaterial are defined according to Pendry's model, then the wave equation in the cloak is derived, and through...
In this paper, we present a novel microstrip patch antenna specifically designed using planar metamaterial patterned substrate. It is developed based on an ordinary patch antenna, and isolated triangle gaps and crossed strip-line gaps are etched on the metal patch and ground plane respectively. This patterned substrate was demonstrated in literature to have left-handed characteristics. In this way,...
In this paper, the far field properties of the lossless metamaterial covered perfectly conductor and air cylinder are discussed. The model configuration is given. Under different geometrical and electromagnetic parameters, the far field properties of the model are investigated through the directivities and normalized radiation resistances. Important regularity is obtained.
In this paper, an improved miniaturized cavity resonator (IMCR) dependent on double negative metamaterial (DNG) and epsilon-negative material (ENG) layers is designed and optimized. The length and width of the IMCR are simultaneously shortened to the half of a conventional cavity resonator. The IMCR is numerically simulated, results show that the resonance phenomenon in the IMCR is observed clearly,...
On the basis of spherical vector wave functions in uniaxial anisotropic left-handed materials (LHMs) and the first, second, third and fourth spherical vector wave functions in uniaxial anisotropic LHMs satisfy the same differential equation, the electromagnetic fields in uniaxial anisotropic LHMs can be expressed as an addition of the first and second spherical vector wave functions in uniaxial anisotropic...
In this paper, a compact LHM, which unit electrical cell size is 0.07 and relative bandwidth is 27%, is designed with CST's MWS simulation tools. The effective permittivity and effective permeability of the LHM are extracted from the reflection and transmission data based on improved NRW approach. Calculation results show that the effective permittivity and effective permeability are simultaneously...
In this paper, a multilayered cylinder filled with metamaterials is studied. General formulas of electromagnetic fields in each region are derived using the eigenfunction expansion method. For an infinite line source, the image property is observed when the radius of this cylinder is much larger than the wavelength. The distributions of electromagnetic fields are presented when a line source is placed...
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