International Journal of Applied Electromagnetics and Mechanics - Volume 47, issue 2

Authors: Tian, Lulin | Tian, Yaqi | Tian, Qi | Jia, Rong

Article Type: Research Article

Abstract: The cost of precision conical permanent magnetic bearings (PMB) is very expensive in the engineering manufacture. Step conical PMB, which consists of by piling up several couples PM rings of different diameters with rectangular cross section, in a conic disposition, characterized by such advantages as low cost and easy manufacture. Based on the magnetic field of planar point magnetic charge, virtual work principle, and superposition theorem, combining two parallel rectangular section permanent magnets (PM) and …the structure trait of step conical PMB, the magnetic force analytical model of step conical PMB is established, and the relationship between magnetic force and structure parameters of step conical PMB is analyzed, and the correctness of the magnetic force analytical model is validity by ANSYS simulation, comparisons show that the analytical solution closely matches with the results of the finite element analysis. The results indicate that the magnetic force of step conical PMB is proportional to the magnetic annular average perimeter and the square of residual magnetism induction density, and that the magnetic force increases with an increment in the magnetic annular section size, the axial magnetic force increases with an increment in the axial deflection, the radial magnetic force increases with an increment in the radial deflection. The paper provides technical support for design and structure parameters optimization of step conical PMB. Show more

Keywords: Step conical permanent magnetic bearing, magnetic force, analytic model, ANSYS simulation

DOI: 10.3233/JAE-130130

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 293-304, 2015

Authors: Yu, Xudong | Long, Xingwu

Article Type: Research Article

Abstract: This paper presents a mathematical model and a finite element model to investigate the model parameters of mechanical dither in a ring laser gyroscope in which the bimorph piezoelectric actuator are employed as driving mechanisms to avoid the problem of so-called lock-in effects. The validity and efficiency of the mathematical model and finite element model are conformed by comparing with the sinusoidal experimental results, and the errors are 3.14% and 1.79% respectively. Moreover, the parametric design …for the geometric dimensions of mechanical dither and the bimorph piezoelectric actuators is easily achieved through finite element model. It is shown that careful selection of the structural parameters allows the resonant frequency to be suitable. These results are important for the mechanical dither design and improvement of high accuracy ring laser gyroscopes and inertial navigation system. Show more

Keywords: Dithered ring laser gyroscope, mechanical dither, bimorph piezoelectric actuator, finite element analysis

DOI: 10.3233/JAE-140008

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 305-312, 2015

Authors: Xu, Lizhong | Zheng, Fengjie | Peng, Lingchao

Article Type: Research Article

Abstract: The railgun system is an electromechanical coupled nonlinear system. Here, considering the electromagnetic force nonlinearity of the rail, the electromechanical coupled nonlinear dynamic equations for the rail are proposed. Using these equations, the nonlinear vibrating frequencies of the railgun system and their changes along with the system parameters are investigated. The amplitude frequency characteristics of the rail are discussed. The results show that the electromagnetic nonlinearity should be considered for a small …stiffness of the elastic foundation, small distance between the two rails, and a large rail current. The results can be used for dynamic performance design of the railgun system. Show more

Keywords: Railgun, free vibration, nonlinearity, rail, electromechanical coupled

DOI: 10.3233/JAE-140011

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 313-322, 2015

Authors: Chawla, Paras | Khanna, Rajesh

Article Type: Research Article

Abstract: The full-wave analyses and design of a multiband reconfigurable antenna (MRA) using radio frequency microelectromechanical system (RF MEMS) switches is presented for 1.0–10.0 GHz band. Integration of spiral antenna and MEMS switches on a conventional FR4 printed circuit board (ε_r = 4.4 and tanδ=0.002) is designed. This paper also gives the construction and performance of low loss MEMS resistive switches and further describes the important improvements in the construction of the …switches. The RF switches used here exhibit very good RF characteristics with typical values of pull-in voltages lies between 3.5 to 20.25 V. The cantilever beam structure of Design-3 switch offers pull-in voltage as low as 3.5 V at air gap g_0= 0.5 μm. Further, Design-1 switch have insertion losses lower than 0.39 dB in ON position, and isolation of "Design-2" switch as high as 79.83 dB in OFF position. As compared to all presented switches the "Design-3" switch has optimized displacement time response i.e. 2 ms. The effect of optimized "Design-3" switch is than study along with spiral antenna. The overall arm length of spiral is changed by activating and deactivating the three "Design-3" switches and consequently its frequency reconfigured. Finally, optimization procedure using quasi Newton method is introduced for characterizing antenna by changing slot length. The wide bandwidth ranging from 200 MHz to 1.65 GHz at different multiband of proposed MRA indicates device contribution in enhancing the mobile TV and internet application speed. Show more

Keywords: Finite element methods, electromagnetics, microelectromechanical systems, antennas, Newton method, mobile RF front end

DOI: 10.3233/JAE-140018

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 323-335, 2015

Authors: Meng, Licheng | Gao, Cun-Fa

Article Type: Research Article

Abstract: This work studies on the classical electro-mechanical problem of an electrostrictive plate with an elliptical hole. In the present work, the isotropic case for the electrostrictive plate is considered based on the small strain assumption. The solutions are then provided by the complex variable method for an infinite plate with an elliptic hole or a crack. Moreover, FEM analyses where a 3D electrostrictive element is defined in ABAQUS user subroutine UEL are presented for a finite …plate. Numerical results are given to discuss the effects of plate geometries, applied electric fields, material properties, the electric body force and Maxwell stress tensor on the stress fields around the elliptical hole. It is found that the traditional uncoupled treatment may cause an unpredictable inaccuracy and a coupled analysis is needed in general. Show more

Keywords: Electrostrictive plate, elliptical hole, complex function method, FEM

DOI: 10.3233/JAE-140045

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 337-371, 2015

Authors: Zhao, Wei | Zhang, Yong | Li, Li | Liu, Shuang | Xu, Ruimin

Article Type: Research Article

Abstract: In this paper, an improved wideband millimeter-wave 180° hybrid is proposed and a novel W-band broadband single balanced mixer based on the new hybrid is presented. The proposed hybrid consists of a standard waveguide to suspended coplanar waveguide (SCPW) transition and a SCPW to suspended stripline transition. According to the inherent electromagnetic field characteristics of the two transitions, the proposed hybrid achieves good performances of broadband phase, power distribution and isolation. The …simulated insertion losses of the two transitions and the isolation between the two signal input ports are better than 0.1 dB and 54 dB respectively. A single balanced mixer based on the proposed hybrid has been designed and fabricated at W-band. The measured single-sideband (SSB) conversion loss is less than 9.5 dB for the radio frequency (RF) range from 80 to 108 GHz. And the best SSB conversion loss of 5.8 dB is achieved with RF of 104 GHz. Moreover, the local oscillator (LO)-RF isolation is more than 30 dB over the overall W-band. The results show that the fabricated mixer has the advantages of broad bandwidth, low conversion loss, and good isolation. Show more

Keywords: 180-degree hybrid, broadband, mixer, millimeter-wave, W-band

DOI: 10.3233/JAE-140048

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 373-379, 2015

Authors: Zhang, Z. | Jiao, Y.C. | Weng, Z.-B. | Wang, X.-M.

Article Type: Research Article

Abstract: Based on the double resonant properties of the complementary hook-shaped resonator (CHSR), a novel miniaturized dual-band microstrip filter is proposed for WLAN operations. The filter, which is only 0.067 λ_0 × 0.084 λ_0 in overall dimensions, is composed of two opposite CHSRs and modified T-shaped feed-lines. Two hook-shaped strips generate two respective passbands, independently. The proposed filter is found to have two transmission zeros around the high resonances …for improved selectivity. To verify the proposed method, a dual-band filter is implemented and measured, and the measurement results agree well with the simulated data. Show more

Keywords: Compact, complementary hook-shaped resonator (CHSR), bandpass filter (BPF), dual-band BPF

DOI: 10.3233/JAE-140052

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 381-387, 2015

Authors: Wang, Yuezong | Ma, Guodong | Zhang, Chenchen

Article Type: Research Article

Abstract: An electromagnetic-driven microgripper is designed for the automatic process of gripping micro-coil wire under the guidance of Stereo Light Microscope (SLM) visual system. The diameter of the wire is about 50–70 μm. Stress analyze with the ANSYS simulation software helps to obtain stress and safety factor contours of the upper and lower clamp arm when the microgripper grips wires. Simulation results show the correctness and reliability of the design. The microgripper clamping force is …up to 0.9 N by theoretical calculation. Test results show that this gripper achieves a displacement of 1.1 mm. Functional test for the wire traction microgripper has been done under the guidance of SLM visual system. The wire traction microgripper is placed in three-dimensional platform, and the three-dimensional platform moves microgripper in the SLM object space close to the clamped object. Positioning accuracy error is determined by repeated positioning precision experiments on three-dimensional platform by the laser displacement sensor. Automatic process of gripping the micro-coil wire is observed and recorded in the SLM visual system to verify performance of the microgripper structure design. Show more

Keywords: Electromagnetic-driven, microgripper, ANSYS simulation, stress analysis

DOI: 10.3233/JAE-140056

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 389-397, 2015

Authors: Dwivedi, Surabhi | Mishra, Vivekanand | Kosta, Yogesh P.

Article Type: Research Article

Abstract: The variation in the spacing height of a metamaterial cover over the slotted patch antenna is reported to improve its directivity. HFSS software is used for simulations. An antenna is designed with a metamaterial cover to work in three bands within the frequency range of 1–4 GHz. A comparative result analysis of the effect of varying the spatial height of the metamaterial cover over patch antenna is shown theoretically. The proposed novel slotted patch antenna design …has triband operation in the frequency range of 1–4 GHz with the miniaturized overall antenna size of the dimension 52.5 mm × 36.5 mm × 1.56 mm, that is equivalent to miniaturized design reported to our knowledge so far. For the very first time, the concept of Newton's divided difference method is applied for evaluating the performance parameters of the antenna. A global formula is developed to indicate the relationship of the directivity with the spatial height. The designed model has various applications in the field of satellite, aeronautical and optical communications mainly in the frequency range of L and S band. Show more

Keywords: Directivity, metamaterial cover, microstrip patch antenna, high frequency structure simulator, Newton's divided difference method, slotted patch antenna

DOI: 10.3233/JAE-140060

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 399-409, 2015

Authors: Guo, Bin | Chen, Zhongsheng | Cheng, Congcong | Yang, Yongmin

Article Type: Research Article

Abstract: This paper presents a nonlinear rotating vibration energy harvester by employing a piezoelectric cantilever beam and a nonlinear magnetic force due to a pair of magnets. A mathematical model is derived for the nonlinear rotating harvester based on the Lagrange's equation and the assumed-mode method, where piezoelectric coupling behavior is also included. From the model, the potential function of the nonlinear rotating harvester is firstly studied. Then its output characteristics under rotating speeds varying linearly and …nonlinearly with time are carefully examined, respectively. The effects of the distance between the two magnets, the sweep rate, the sweep direction and the growth rate of the rotating speed on the output characteristics are investigated numerically. The simulation results reveal that all these parameters have strong influences on characteristics of the rotating harvester. When an optimal distance is achieved, a nonlinear rotating energy harvester is fit for low frequency and variable rotating motion more than a linear one. All conclusions will provide guidelines for designing nonlinear rotating vibration energy harvesters. Show more

Keywords: Rotating energy harvester, nonlinearity, piezoelectric cantilever beam, variable rotating speed

DOI: 10.3233/JAE-140077

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 411-423, 2015

Authors: Yang, Yang | Zhu, Huacheng | Fan, Lei | Luo, Yan | Zhang, Fuhao | Huang, Kama

Article Type: Research Article

Abstract: A two-port U-shaped Coplanar Waveguide (U-CPW) used for broadband complex permittivity measurement of high loss solutions is presented. Compared with the one-port measurement device, this two-port U-CPW coupled with artificial neural networks algorithm has the ability of reducing the multiple-solutions. Also, the measured T/R (transmission/reflection) coefficients were used instead of simulated reflection coefficients for training the neural networks that enhanced the accuracy of measurement results. Two real-valued neural networks associated with the …U-CPW are used to reconstruct the two parts of the complex permittivity separately from the measured T/R coefficients. First, a large number of measured T/R coefficients of broadband frequency points of ethanol-water mixtures along with their theoretical complex permittivity are used to train two separate neural networks. Second, the trained networks are employed to reconstruct the complex permittivity of other solutions using the measured T/R coefficients. Compared with the results of Cole-Cole equation, the reconstructed results of methanol-water mixtures and ethanol-methanol mixtures at different volume fractions have been obtained with sufficient degree of accuracy in the frequency range 1–3 GHz at 20°C. For predicted values using the developed artificial neural network (ANN) architecture and those obtained from literature, the average relative errors of real and imaginary parts of complex permittivity are 2.27% and 2.12%, respectively. Show more

Keywords: Complex permittivity, artificial neutral network, coplanar waveguide, broadband measurement, transmission/reflection coefficients

DOI: 10.3233/JAE-140078

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 425-432, 2015

Authors: Liu, Yufeng | Chen, Xing | Xu, Guanghui | Liu, Changjun | Huang, Kama

Article Type: Research Article

Abstract: A novel microstrip-fed dielectric rod array antenna with high end-fire gain is proposed. It has simple structure, comprising a group of cylindrical dielectric rods and a microstrip corporate feeding network, and is low in cost. A prototype 4 × 4 array working at 8.0 GHz is designed, fabricated and measured. Simulation and measurement results show the antenna has encouraging performances, e.g. an impedance bandwidth (|S_{11} |←10 dB) of 7.7%, an end-fire …gain up to 20.3 dBi, side-lobes 13.5 dB below the main lobe, and linear polarization with the cross-polarization level less than − 21 dB. Show more

Keywords: Array antenna, dielectric rod, high gain, microstrip corporate feeding network

DOI: 10.3233/JAE-140081

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 433-440, 2015

Authors: Dai, Jianguo | Chang, Siqin | Liu, Liang

Article Type: Research Article

Abstract: This paper presents the research on a problem which is difficult to implement in the actual magnetization process of Electromagnetic Linear Actuator (ELA)'s permanent magnets radially magnetized. Given magnetic field symmetry and assembly feasibility, it creatively puts forward four parallel magnetized-permanent magnets joint schemes (PM-PMs Joint Schemes) of the ELA. On the basis of mathematical modeling and simulating calculation, further study on the comparison of magnetic field effects and ELA's performance in different …joint schemes is accomplished. Then, through the Analytic Hierarchy Process (AHP), 8 parallel magnetized-permanent magnets joint model (8 PM-PMs Joint Model) is determined as the best choice after optimizing selection. Further, the 8 PM-PMs Joint Scheme is trial-produced and its air gap flux density and electromagnetic force are also tested. Compared with simulating calculation, the maximum error from test result is within 4.3%, verifying the accuracy of mathematic model and simulating calculation. Show more

Keywords: Electromagnetic linear actuator, radial magnetization, parallel magnetization, joint model, analytic hierarchy process

DOI: 10.3233/JAE-140054

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 441-451, 2015

Authors: Tiwari, D.K. | Awasthi, M.K. | Agrawal, G.S.

Article Type: Research Article

Abstract: We study the electrohydrodynamic capillary instability of the interface between two uniform superposed viscous and electrically conducting fluids in the presence of a free surface charge, when there is heat and mass transfer across the interface. The fluids are subjected to the uniform electric field in the axial direction and the viscous potential flow theory is used for the investigation. A quadratic dispersion relation that accounts for the growth of disturbance waves is derived for the …linear stability analysis and the stability of the system is analyzed theoretically and numerically. The stability criterion is given in terms of the critical value of applied electric field as well as critical wave number. Various graphs with respect to physical parameters such as electric field, heat transfer coefficients, conductivity and permittivity ratio are drawn and effect of various parameters is described. It is observed that free surface charge and electric field both have stabilizing effect on the stability of the system. Show more

Keywords: Capillary instability, electrohydrodynamics, free surface charge, heat and mass transfer

DOI: 10.3233/JAE-140009

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 453-465, 2015

Authors: Cui, Xiaobin | Hu, Junhui

Article Type: Research Article

Abstract: This paper presents experiments and finite element (FE) analyses of an infrasonic vibration energy harvesting device in which a low-frequency pendulum impacts a cantilever beam type energy harvester. The experiments demonstrate that the energy harvester operates in the frequency range of 2∼8 Hz and has output power of several microwatts under 0.1 g excitation acceleration. Moreover, a finite element model with a coupling of impact, vibration, piezoelectricity and circuit is established and used to …analyze the output voltage and power. The frequency response characteristics at different pendulum lengths and the distances between the pendulum ball and cantilever beams are measured and calculated, respectively. Useful guidelines for designing the energy harvester are obtained. Show more

Keywords: Infrasonic vibration, energy harvester, pendulum, FEM simulation

DOI: 10.3233/JAE-140068

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 467-474, 2015

Authors: Shi, Jia-Ming | Yuan, Zhong-Cai

Article Type: Research Article

Abstract: The filter properties of the electromagnetic wave in one-dimensional plasma photonic crystals with defects, which consist of unmagnetized plasmas and microwave lossy dielectrics (MLDs), were studied by the Finite Difference Time Domain (FDTD) method in this paper. The results were presented that the thickness, the plasma angular frequency, and the dielectric relative permittivity in the defect layer can influence the filter properties in the plasma photonic crystals. As a possible application, the transmission and …filter characteristics of the plasma photonic crystal under incident high power wave were discussed. Show more

Keywords: Filter, defect, plasma photonic crystal, FDTD

DOI: 10.3233/JAE-140064

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 475-482, 2015

Authors: Sahraoui, Mohamed | Ghoggal, Adel | Zouzou, Salah Eddine | Guedidi, Salim

Article Type: Research Article

Abstract: This paper proposes an improved rotor fault detection algorithm. The main objects are: First, ameliorate the reliability of the rotor fault detection task especially under very low load in the presence of industrial frequency inverter. Second, allow even relatively unskilled users to make an automatic, fast and reliable decision on machine health with low requirements. Basing on the concept of multiple signature processing, the proposed algorithm uses Relative Harmonic Indexes (RHI) as a new fault indicator. …The RHI are computed starting from many harmonics selected carefully according to their sensitivity to the occurrence of rotor bar faults, this represents its main advantage compared to the classical fault indicators which use only one or two fault signatures leading commonly to erroneous diagnosis especially under low load. The proposed algorithm requires only the stator current signal. For each data acquisition, the algorithm computes, normalises and classifies the RHI then it displays the obtained results in a simple manner. Extensive experimental tests, carried out on a 3 kW squirrel cage induction motor fed from an industrial frequency inverter, confirm the effectiveness of the proposed algorithm in detecting of rotor bar fault under different operation conditions even with very low loads. Show more

Keywords: Fault diagnosis, fault indicator, induction machine, broken rotor bars, algorithm

DOI: 10.3233/JAE-140021

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 483-502, 2015

Authors: Wang, Hanfeng | Lv, Qiang | Fang, Yong | He, Yigang | Bao, Xiaohua

Article Type: Research Article

Abstract: This paper presents a multi-position magnetic field measurement approach to detect air-gap eccentricity in induction machines, including static, dynamic and mixed eccentricity. Using this method, the position of minimum air gap of static eccentricity also can be detected. The sideband components around the fundamental frequency of magnetic flux leakage in stator yoke is particularly analyzed based on magnetic circuit. The magnitudes of induced voltage harmonics in search coils are also investigated by finite …element method. The algorithm is implemented for a 4-pole three-phase cage induction machine with static, dynamic and mixed eccentricity. It is highlighted that dynamic eccentricity can be detected by any one of the search coils, static eccentricity and the position of minimum air gap can be detected by the magnitudes of induced voltages in all the search coils. The theoretical results have been validated by finite element method. Show more

Keywords: Eccentricity, fault detection, induction machines, magnetic field measurement

DOI: 10.3233/JAE-140037

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 503-512, 2015

Authors: Tang, Enling | Shi, Xiaohan | Zhang, Qingming | Wang, Meng | Wang, Di | Xiang, Shenghai | Liu, Shuhua | Xia, Jin | He, Liping | Han, Yafei

Article Type: Research Article

Abstract: Impact light flash is an intense light flash released when a target is impacted by a hypervelocity projectile. Light flash is caused by emissions from a jet of shocked material which is thrown from the impact site. Impact light flash phenomenology is now being considered for applications where remote diagnostics are required to observe and diagnose impacts on satellites and spacecraft. Additionally, this phenomena and remote diagnostics are under consideration for deep space exploration and missile …defense applications. Currently, optical signatures created from hypervelocity impact can be utilized as the basis for detectors (spectrometers, pyrometers), which characterize the material composition and temperature. To establish this capability technically in the laboratory, we have conducted a series of experiments on a two-stage light gas gun at impact velocities ranging from 1.96 to 4.21 km/s. The focus of this work is to develop a flash signatures collected methods for use as a reliable light flash, and late time radiating evolution to characterize material behavior in the shocked and expanding state; ascertain scaling of light flash with impact velocity, and determine the temperature of the impact flash resulting from radiating emissions when photomultiplier tube (PMT) are used in conjunction with narrow band pass filtering at specific wavelengths as a pyrometer. The results of these experiments are discussed in detail using natural dolomite target. Show more

Keywords: Hypervelocity impact, impact flash, natural dolomite plate, optical-fiber pyrometer

DOI: 10.3233/JAE-140015

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 513-521, 2015

Authors: Sharma, M.M. | Deegwal, J.K. | Govil, M.C. | Kumar, Ashok

Article Type: Research Article

Abstract: A compact printed ultra-wideband (UWB) antenna with two notched stop bands is analyzed and presented. By introducing a unit complementary split ring resonator (CSRR) in the beveled edges of radiating patch, two sharp notches are achieved at frequencies of 3.5 and 5.8 GHz. The proposed antenna has been fabricated and experimentally tested. A good agreement between simulated and measured results has been observed. Measured impedance bandwidth of the tested antenna is 3.12–12 GHz, which covers bandwidth …requirement of UWB frequency band, for VSWR < 2 and also has two notched stop bands of 3.39–3.90 and 5.52–6.44 GHz, for VSWR > 2, for rejecting WiMAX and WLAN band signals, respectively. In addition, the effect of the dimensions of the CSRR on the two stop bands is also analyzed. The radiation pattern and gain characteristics of the proposed configuration are studied and the results are exhibited accordingly. Show more

Keywords: UWB, stop band, complementary split ring resonator, WLAN, WiMAX

DOI: 10.3233/JAE-140007

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 523-531, 2015

Authors: Weng, Yin-Kan | Li, Song | Yang, Jin-Ling | Zhou, Hui | Yi, Hong | Wang, Hong

Article Type: Research Article

Abstract: In this paper, a kind of efficient solution to the trihedral corner reflector's (TCR's) radar cross section (RCS) is proposed. Based on the combination of geometrical optics (GO) and Gordan surface integral method, TCR's RCS was computed and was compared with the results from computational electromagnetics software FEKO. Good agreement and significant speedup achieved show that the method mentioned in this paper is capable of practical rapid simulation and design, especially suitable for electrically large plate …structure. Show more

Keywords: Geometrical optics, gordan surface integral method, trihedral corner reflector, radar cross section, FEKO

DOI: 10.3233/JAE-130156

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 533-539, 2015

Authors: Strecker, Z. | Roupec, J. | Mazůrek, I. | Klapka, M.

Article Type: Research Article

Abstract: Magnetorheological dampers seem to be suitable for the adaptive car suspension systems. For proper operation of the semi-active algorithms (skyhook, groundhook), the force response of the damper must be fast enough. In this paper, the response time of the Delphi vehicle MR damper is examined and the sources of the overall force time response on the control voltage are discussed. One of the main sources of the response time seems to be electro-magnetic circuit of the …MR damper. A principle of an optimal controller for reducing response of the coil's current on the control voltage is designed. However, the measured overall force time response with fast current controller was not reduced as expected. Therefore, a FEM simulation of the magnetic circuit was made. It shows that after an optimization of the current controller, eddy currents in the coil's core cause long time response and therefore they are the limiting factor of the response time of the MR damper. These simulations were verified by the measurements and some recommendations about improving the pistons construction are given at the end. Show more

Keywords: Magnetorheological damper, MR, time response, pulse-width modulation, eddy current

DOI: 10.3233/JAE-140006

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 541-550, 2015

Authors: Chen, Junjie | Huang, Songling | Zhao, Wei

Article Type: Research Article

Abstract: In this paper, we propose an equivalent forward model of magnetic flux leakage (MFL) inspection in pipelines to reduce the computation effort to predict MFL signals. Then an iterative simulated annealing inversion procedure is developed to reconstruct the three-dimensional (3-D) defect profile from MFL signals. Experiments results, based on both simulated and measured MFL signals, demonstrate that the proposed inversion procedure using the equivalent forward model has high performance in terms of execution speed and accuracy.

Keywords: Magnetic flux leakage, equivalent model, defect reconstruction, pipeline inspection, simulated annealing algorithm

DOI: 10.3233/JAE-140022

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 551-561, 2015

Authors: Patel, Amit | Kosta, Y.P.

Article Type: Research Article

Abstract: This paper presents a novel transversal coupling network for the design of multiple-band bandstop filters. In this proposed structure, multiple-band bandstop filter is design based on amalgamated (conductive and dielectric material) posts coupled rectangular waveguide to demonstrate the feasibility of proposed network. We have proposed two structures using four metallic windows placed at the corners of triangle inside a waveguide and symmetrical dielectric material posts placed at the center of the triangle made …by metallic posts. By inserting dielectric post, the results are improved. The structures are simulated with Ansoft's finite-element High Frequency Structure Simulator tool and its equivalent circuit of Ansoft designer to demonstrate the characteristics of this notch filter using a rectangular waveguide with center frequency of 11.2 GHz. The proposed structure using amalgamated post is fabricated and tested using the Vector Network Analyzer and obtained results compared with the simulated results. Show more

Keywords: Conductive {and} dielectric posts, waveguide resonator, scattering parameters, rejection bandwidth {and} quality factor

DOI: 10.3233/JAE-130158

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 47, no. 2, pp. 563-581, 2015