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This paper presents a substrate integrated image guide (SIIG) transmission line based on the normal PCB technology. Air holes are cut directly on a metallized PCB, so that this kind of SIIG offers better fabrication reliability and lower assembly cost. However, these holes caused unwanted leakage loss. To overcome this problem, the width of the guiding channel should be chosen carefully. Then, a leaky-wave...
Present paper highlights a modified offset cross slotted array antenna at Ka band, in which (26 × 10) number of element has been used to achieve a circularly polarized narrow beam antenna. Analysis has been carried out by taking into account of three compound slots, positioned at a quarter offset broadwall of waveguide. Incorporation of complex slot pair and offset center cross slot improves the axial...
In this paper, a refined shift-and-invert Arnoldi technique is used to speed the convergence rate of a large scale nonsymmetrical generalized eigenvalue problem by using refined Ritz vectors to approximate the desired eigenvectors. The finite difference frequency domain (FDFD) method combined with refined shift-and-invert Arnoldi can be used to analyze the properties of arbitrary complex close/open...
Neural networks (NNs) have been widely used in microwave device modeling. One of the greatest challenges is how to speed up the model training process and reduce the development cost. To address the issue, this paper exploits FPGAs to accelerate NN training. Experimental results demonstrate that the model training time can be reduced by up to 99.1%, compared to the traditional software implementation.
A microstrip reflectarray antenna using fragmented patches as its reflection elements is proposed. The fragmented patch is gridded into 2N×2N pixels, each of which is randomly assigned either conducting or non-conducting property, and in this way different reflection phases is provided owing to their variable configurations. A microstrip reflectarray antenna with 7×7 fragmented elements is designed,...
This paper presents a novel technique for the numerical modeling of piecewise-homogeneous waveguide components. The component is segmented into homogeneous boxed building blocks, and the generalized admittance matrix of each building block is determined by the Boundary Integral-Resonant Mode Expansion (BI-RME) method, using the Ewald technique to calculate the Green's function of the box. The frequency...
In this article, simulation and implementation of a 30 watt high efficient class-AB RF pulse power amplifier using GaN transistor in 1.2–1.4 GHz is presented. Class-AB RF amplifier is widely used in wireless communication industry due to acceptable compromise between linearity and efficiency. Load pull utility provided in Agilent Design System software is employed to obtain the optimum load impedance...
A highly efficient Multi-Level Green's Function Interpolation (MLGFI) accelerated stable full-wave integral equation algorithm is proposed for the first time to model the low frequency coupling problems in near-field wireless transfer with linear computational complexity. Numerical results validate its accuracy and efficiency. This algorithm has been used to analyze the magnetic couplings between...
Novel analytical model for bonding wire has been proposed in this paper. Bonding wires on stacked dies with different connection paths have been modeled and simulated at high frequency. Return loss demonstrated that the transfer connection path showed better transmission performance. Furthermore, the relationship between materials with different dielectric constant and return loss were investigated...
This paper presents a novel substrate integrated dual-wideband magneto-electric (ME) dipole antenna for WLAN and WiMAX applications. By employing a ladder-shaped feeding structure to excite the dual-layer electric dipole radiated patches, a dual-band feature can be acquired. Besides, by using the ladder-shaped feeding structure and the printed metal via technology, the impedance matching can be easily...
Impedance mismatch between antenna and its feeding port, and between other connecting ports will directly affect antenna gain measurement results. A full-port impedance mismatch model based on signal flow analysis and corresponding correction formula has been developed, and correction values can be obtained by using measured scattering parameters. The impedance mismatch correction uncertainty and...
The interaction of a Gaussian pulse with a negative permittivity metamaterial slab is presented. The results of this numerical study predict the propagation behavior of electromagnetic wave in presence of the slab. To perform this analysis the Auxiliary Differential Equation Finite Difference Time Domain (ADE-FDTD) analysis for a dispersive medium using Drude model is used. The negative permittivity...
Secular dynamics of charged particles in the vortex electromagnetic wave beam is widely used in many ranges. However, the conventional numerical schemes for this problem are failed when the charged particle velocities reach up to relativistic region. The coherent accumulation of numerical errors may destroy the simulation and introduce pseudo physics. To obtain an applicable numerical tool for secular...
In this paper, a X-band broadband antenna array with 4-elements is designed and fabricated. Firstly, various methods, such as multi-resonant and slot-coupling, are applied hybridly to broaden the bandwidth of the ordinary microstrip antenna element. Simulation results show that VSWR<2 bandwidth of the proposed antenna is over 50%, with center frequency of 10GHz. Then, in order to achieve high gain,...
A compact resistive-feedback CMOS low-noise amplifiers (LNA) is presented for wideband applications. The LNA is based on a common source (CS) amplifier with gate inductive peaking, resistive feedback, and source degeneration inductive topologies to achieve the wideband matching networks The LNA is fabricated in a standard 0.18-μm RF CMOS technology. Under power consumption of 10.87 mW with 1.5-V power...
This paper deals with the Model Order Reduction applied locally in the Finite Element Method (FEM) analysis. Due to the reduction process, blocks of FEM system matrices associated with selected subregions of the computational domain are projected onto the subspaces spanned by the vectors of suited orthogonal projection basis. In effect, large and sparse FEM matrices are replaced with small and dense...
Different kinds of a priori information used to enhance microwave tomography are introduced and classified into two main categories. The first main category of a priori information is about features of target, these can introduce some information of the target to the tomography algorithm. This type of a priori information can lead to a better initial guess and an appropriate regularization as well...
Subgriding is much desirable for FDTD modeling of small structures in large structures. However, it has remained to be very challenging for its instability. In this paper, we propose a simple subgridding scheme that takes advantage of the explicit unconditionally stable finite-difference time-domain (FDTD) method free of unstable modes: it is applied to the coarse mesh regions with larger space steps...
The late-time instability has been an issue of main concern for time-domain integral equation (TDIE) method using the march-on-time algorithms. It can be identified with by analyzing the eigenvalues of the synthetic impedance matrix of the methods. In this paper, we reformulate the TDIE methods and analyze the late-time instability of different types of TDIE. A new category of the eigenvalues is presented...
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