Search

The charging coil plays an important role in the wireless charging system system. However, there are still some problems in the design of the wireless charging coil, such as the low coupling coefficient. In order to improve the coupling effect, this paper proposes an optimized design scheme for the metal shielding layer structure of DD coil. Firstly, the influence of the structure size of DD coil metal plate on the coupling coefficient is studied by the mathematical modeling analysis. Futhermore, the maxwell simulation is used to study the metal plate coupling coefficients with varying structure sizes, addressing receiving uniformity issues. The optimal size of the shielding layer is designed for optimal magnetic coupling in wireless charging. Finally, this paper validates the feasibility of the improved metal shielding layer through experiments. The research in this paper may have a reference role in the wireless charging system of electric vehicles. [ABSTRACT FROM AUTHOR]

In this paper, a miniaturized single band-stop frequency selective surface (FSS) with higher order of angular stability and polarization insensitivity is utilized to reconfigure the radiation patterns of a monopole antenna, forming end-fire-like radiation patterns at 5.2 GHz. A mathematical analysis based on pattern multiplication is presented to suggest the arrangement of the FSS to achieve the end-fire-like radiation patterns from the monopole antenna. According to this analysis, the monopole radiator needs to be shielded from three sides, two parallel vertical sides and the top of the antenna. The FSS shows great angular stability with the incidence angle ranging from 0° to 80° for both TE and TM polarizations, resulting in stable end-fire-like radiation patterns when it is used with the monopole antenna. The monopole antenna along with the FSSs were fabricated and tested successfully, thus verifying the functionality of the FSSs in shaping the beam of the antenna. [ABSTRACT FROM AUTHOR]

In this paper an optical transfer function for description of the operation of complex fiber Bragg Gratings similar to electrical ones is presented (H(jω)). For this purpose and reconstruction of the transfer function, the Genetic Algorithm (GAs) is used to find optimum number of poles and zeros from the measured reflection coefficient. After building the transfer function according to the developed algorithm in this paper, the reflection coefficient for this approximated system is obtained (simulated) and compared with measured values. The results obtained from the approximated transfer function in these cases are so close to real measured data. So, the presented method introduces an interesting approach for identification of the complex Bragg Gratings in frequency domain. Some of optical characteristics (both frequency domain and time domain parameters) of these systems can be extracted from the approximated transfer function easily. [ABSTRACT FROM AUTHOR]

The intra-channel collision of optical solitons, with parabolic law non-linearity, is studied in this paper by the aid of quasi-particle theory. The perturbation terms that are considered in this paper are of Hamiltonian type. The suppression of soliton-soliton interaction, in presence of these perturbation terms, is achieved. The numerical simulations support the quasi-particle theory. [ABSTRACT FROM AUTHOR]

In this paper, a novel vector modulator (VM) that precisely controls the magnitude and phase of input signals simultaneously is proposed. The proposed VM consists of low phase deviation attenuators, a 90° hybrid splitter, and Wilkinson power combiner. In order to overcome the phase deviation characteristics found in the conventional attenuators, the novel phase compensation technique has been adopted and mathematically analyzed. Linear vector arrays along the center point with large signal magnitude variations in a full 360° phase control are achieved on a polar plane by the proposed VM. [ABSTRACT FROM AUTHOR]

The transmission characteristics in antipodal finline are analyzed by edge-based finite element method. The cutoff wavelength of the dominant mode and single-mode bandwidth can be changed by adjusting the thickness of metallic fins and dielectric constant of dielectric substrate. Field patterns of the dominant mode and the first higher-order mode for different dimensions and the dielectric constant of dielectric substrate are also illustrated. Numerical results in this paper are considered useful in practical applications. [ABSTRACT FROM AUTHOR]

Based on L-type dual-band impedance matching structure, this paper presents a new symmetric modified Wilkinson power divider for dual-band applications. In the matching structure, two transmission line stubs can be used to implement impedance matching and space isolation for two transmission ways, simultaneously. In the isolation structure, a single resistor is applied, and the design values are adjusted according to the center frequency ratio. In this proposed power divider, the ideal matching of all ports, equal power splitting and isolation between the output ports can be achieved. Theoretically, the nonlinear design equations for normalized parameters are directly derived based on the conventional even- and odd-mode analysis. In microstrip experiments, simulated and measured results of two fabricated power dividers with different frequency ratios are given. It can be clearly seen that there are good agreements between the theoretical and experimental results. [ABSTRACT FROM AUTHOR]

This paper deals with the numerical analysis of the interaction of two reconfigurable antennas deployed in the reflection mode usually exploited in Ground Penetrating Radar surveys. The two reconfigurable antennas have the same geometry, and the design of the single antenna was presented in [1] for a work frequency band 0.3–1 GHz. The design of the single antenna had the aim of resembling a continuous bow-tie antenna. Here, we extend the previous analysis in [1], limited to a single antenna, by investigating the effect of the receiving antenna on the radiation properties of the transmitting antenna on dependence of the distance between them. [ABSTRACT FROM AUTHOR]

In this paper, we study two different methods, called Legendre and LMS, to find the current distribution of an unequally spaced array structure. In both methods, we aim to find the most similar radiation pattern to a desired one toward an arbitrary angle and then show the ability of LMS method to provide the low SLL (Side Lobe Level) comparing to Legendre method due to its better performance for minimizing error. [ABSTRACT FROM AUTHOR]

An evolutionary optimization method for patch antenna designs is presented in this paper. The modified particle swarm optimization (MPSO) based on fitness distance ratio (FDR) is combined with standard software IE3D to achieve the optimum antenna satisfying a certain design criterion. The antenna geometric parameters are extracted and optimized by a MPSO program, and simulated by IE3D. The fitness function of the optimization is calculated by the MPSO program according to the simulation results extracted from IE3D to represent the performance of each candidate design. A microstrip line fed low-profile E-shaped patch antenna is designed and optimized using the MPSO/IE3D method. The designed patch antenna is simulated, fabricated, and measured to validate the effectiveness of the MPSO/IE3D method. [ABSTRACT FROM AUTHOR]

A novel approach to arbitrary array pattern synthesis utilizing weighted biorthogonal modes is presented in this paper. The algorithm, involving arrays with arbitrary geometry and incorporating mutual coupling effect, can accurately determine element excitations required to yield desired field pattern. The mutual orthogonality of modes is used to ensure the agreement between the desired and computed patterns. The effectiveness of the method is demonstrated with several numerical examples. [ABSTRACT FROM AUTHOR]

In this paper, we derive some original asymptotic expressions to speed up the computation of the excitation vector in the Method of Moments (MoM) numerical analysis of probe-fed planar microstrip antennas. These proposed expressions may be applied to the full-wave analysis of patch antennas in the spectral domain using the asymptotic Greens dyad of the planar integrated structure. It is shown in particular how planar patch antennas fed by a coaxial probe may be efficiently analyzed using fast converging ID integrals to represent the MoM excitation vector, instead of employing the standard spectral bi-dimensional integrals. The numerical results underline the quick convergence of these new expressions and the consequent reduction of the computational time with respect to standard techniques. [ABSTRACT FROM AUTHOR]

In this paper, we describe a vectorial and analytical technique, based on modal transmission-line theory, for solving guided modes of arbitrary shaped cylindrical optical waveguides. The waveguide materials can be either transparent or absorbing. In this technique, mode solving is approached by periodic repetition of the waveguide and using modal transmission-line theory. Pertinent information about guided modes of the waveguide is extracted from transmission-line features. Two examples illustrate the utilization of this technique for analysis of optical waveguides. [ABSTRACT FROM AUTHOR]

In this paper, based on the expressions of the electromagnetic fields in the earth generated by vertical electric and magnetic dipoles situated in the air, by using reciprocity theorem, the complete formulas arc derived for the electromagnetic field of a horizontal electric dipole below the spherical-earth surface. The computations show that the electromagnetic wave attenuates faster along the spherical-earth surface than along the planar-earth surface and the effects of the earth curvature cannot be neglected at large distances between the transmitter and the receiver. [ABSTRACT FROM AUTHOR]

In this paper, a simplified model is developed to treat the mutual coupling effects of adaptive antenna arrays. This model is based on the Neumann expansion technique for matrix inversion. In modeling the mutual coupling effects for an antenna element in an adaptive array, only the direct coupling from its neighbor elements are considered. Numerical examples show that the SINR of an adaptive antenna array including mutual coupling effects calculated with the simplified model is with good accuracy. This model is not only numerically efficient but also gives physical insight into the mutual coupling mechanisms within an adaptive antenna array. [ABSTRACT FROM AUTHOR]

In this paper, an improved image-based propagation model based on a novel polygon-tracing technique in is presented. Unlike other image-based models, it uses generic plane polygons, which we term as ray-polygons, to keep track of rays. Binary Space Partitioning is employed to provide the object visibility order necessary for polygon tracing. The proposed model has a variety of advantages, namely efficient, without reception sphere and ray separation issues, and having less geometrical restrictions. It can be applied equally well in indoor and outdoor environments. [ABSTRACT FROM AUTHOR]