Showing 6 results for Abdolali
M. Kiani, A. Abdolali,
Volume 9, Issue 1 (March 2013)
Abstract
This paper presents a general formulation to investigate the scattering from Multilayer Lossy Inhomogeneous Metamaterial Planar Structure (MLIMPS) with arbitrary number of layers and polarization. First, the dominating differential equation of transverse components of electromagnetic fields in each layers derived. Considering the general form of solution of the differential equations and the boundary conditions of the problem a set of linear equations is obtained. By solving these equations, the electromagnetic fields in all layers and reflection and transmission coefficients are calculated. This method is applied in an interesting example for two bi-layered structures with inhomogeneous conventional material and metamaterial profile for constitutive parameters. Results which are presented in example are useful for constructing general duality between conventional material and metamaterials.
D. Zarifi, E. Hosseininejad, A. Abdolali,
Volume 10, Issue 2 (June 2014)
Abstract
A dual-band artificial magnetic material and then a dual-band double-negative metamaterial structure based on symmetric spiral resonators are presented. An approximate analytical model is used for the initial design of the proposed structures. The electromagnetic parameters of the proposed metamaterial structure retrieved using an advanced parameter retrieval method based on the causality principle show its dual-band nature at microwave frequencies.
A. Abdolali, M. M Salary,
Volume 10, Issue 3 (September 2014)
Abstract
The proposed theorem in this paper is indicative of a kind of duality in the propagation of waves in the dual media of and in the spherical structures. Independent of wave frequency, the number of layers, their thickness, and the type of polarization, this theorem holds true in case of any change in any of these conditions.
Theorem: Consider a plane wave incident on a multilayered spherical structure. The core of structure may be PEC, metamaterial or dielectric. If we apply the interchange or for the constituting materials of the spherical structure and the surrounding medium the radar cross section of the structure will not change in any direction.
D. Zarifi, M. Soleimani, A. Abdolali,
Volume 10, Issue 4 (December 2014)
Abstract
In this paper, the propagation of electromagnetic waves through an infinite slab of uni- or bi- axial chiral medium is analytically formulated for an arbitrary incidence using 4×4 matrix method. In this powerful method, a state vector differential equation is extracted whose solution is given in terms of a transition matrix relating the tangential components of electric and magnetic fields at the input and output planes of the uni- or bi- axial chiral layer. The formulas of the reflection and transmission are then derived. Also, the presented method is verified by some typical examples and the results are compared with the results obtained by the other available methods.
E. Ghasemi Mizuji, A. Abdolali,
Volume 12, Issue 2 (June 2016)
Abstract
The main purpose of this paper is to design, implement and measure a new sample of mantle cloak. A new method called mantle cloak is introduced by cloaking an object by a single, conformal meta-surface which can drastically suppress the scattering of the desired object. In this paper, a grid lattice is placed around a dielectric object as the cloaking structure. Previously, this FSS has been utilized for the cloaking of PEC object; but, since this structure has inductive equivalent circuit on the dielectric, it can be used for cloaking of dielectric cylinder. Numerical simulations of near field and far field of the designed structure are derived to prove the effectiveness of our meta-surface cloak. Also, measurement results of S11 and S21 related to cloaked structure and their comparison with single dielectric proves suitable performance of the designed cloak. The results show more than 20% bandwidth for this structure. This means that this structure is suitable for broadband operations.
H. Rajabalipanah, M. Fallah, A. Abdolali,
Volume 15, Issue 2 (June 2019)
Abstract
An intelligent design method of double screen frequency selective surfaces (FSSs) is addressed in this paper. The employed unit cell is composed of two metallic screens, which are printed on both sides of a substrate. The presented non-trial-and-error approach is investigated based on the separate design of each screen. With the help of some physical intuition and an equivalent circuit model, it is shown that the conventional use of complement geometries restricts the final desired filtering response. Therefore, unlike the previous studies, the metallic screens are not geometrically complementary in this paper. An excellent agreement between the full-wave simulations and corresponding equivalent circuit models has been observed. Using standard lumped elements, a highly selective miniaturized FSS (0.06λ0 ~ 0.08λ0) with two closely-spaced pass bands is designed, for GSM and WLAN frequencies. Simulation results show a dual-polarized characteristic with a good angular stability performance for the proposed structure.
