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