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

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