International Journal of Applied Electromagnetics and Mechanics - Volume 49, issue 3

Authors: Li, Xiang-Chao | Zhou, Zhongshan | Chen, Zehuang | Chen, Puyang

Article Type: Research Article

Abstract: In accordance with the theory of waveguide, the electric field and magnetic field equations of transverse electromagnetic propagating in coaxial line were derived. Based on the equivalent impedance of coaxial line after the broken-down of gas discharge tube (GDT) that connected in parallel, the corresponding relation between reflection coefficient and the equivalent impedance of the main modules at the reflector surface of Z= 0 is established. The high-order mode function of the excitation magnetic current was also analyzed. To solve the transmission and suppression problems of lightning wave propagation, we combined theories with experiment and draw conclusions: a) higher mode …will be excited when the lightning wave propagates on the coaxial line with the line terminal to be open; b) the lightning wave energy will be absorbed by terminal load and higher mode will be also excited when the characteristic impedance of the load is same with the coaxial line; c) the GDT will become a reflector when the lightning wave go through it and part of the wave will be reflected. Part of the energy of the lightning wave will be discharged by GDT and only a little of the energy will be absorbed by the load. The experimental results are consisted with the theories analysis and have a great of significance in practical applications. Show more

Keywords: Waveguide theory, coaxial line, gas discharge tube, lightning, higher mode

DOI: 10.3233/JAE-140130

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 3, pp. 315-325, 2015

Authors: Yu, Xu-Dong | Gao, Na | Xie, Yuan-Ping | Zhang, Peng-Fei | Long, Xing-Wu

Article Type: Research Article

Abstract: The performance of the ring laser gyroscope (RLG) can be affected by variations of the optical path length, due to temperature change and other operation environment factors. This paper focuses on the optimization of the path length control (PLC) transducer to get the largest displacement of the grooved mirror by the finite element method (FEM). To verify the analysis results, a mode-scanning experiment is carried out. The experimental result shows agreement with that of the FEM analysis. We show that a careful selection of material and geometry parameters allows the displacement amplitude to be maximized as 6.48 μm, a value …that is 3 times the displacement in the existing structure. A minimization of the number of mode reset is achieved, leading to an improvement of RLG performance. Show more

Keywords: Ring laser gyroscope, path length control transducer, piezoelectric actuator, design optimization, finite element analysis

DOI: 10.3233/JAE-140136

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 3, pp. 327-335, 2015

Authors: Arehpanahi, Mehdi | Namdar, Reza

Article Type: Research Article

Abstract: In this paper, a new method for mesh refinement in Surface Current Method (SCM) based on combination of uniform and automated mesh refinement is proposed. This method is a fast and accurate method related to the usual SCM mesh refinement method. In this refinement method the ferromagnetic boundaries are divided in to the two sub-boundaries which are called outside and inside boundaries. The outside and inside boundaries are refined by uniform and automated mesh refinement respectively. Therefore the total number of meshes which obtained in this method will be lower than classical SCM refinement. Verification of simulation …results is done using Finite Element Method (FEM). Show more

Keywords: Mesh refinement, surface current method, magnetic devices, uniform mesh refinement, automated mesh refinement

DOI: 10.3233/JAE-140137

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 3, pp. 337-345, 2015

Authors: Zhao, Yang | Deng, Yiming | Yan, Wei | Qiu, Xiaohui | Liu, Yong

Article Type: Research Article

Abstract: In the paper, we experimentally characterized the four methods and assessed both current method and voltage method based on its test schematics. The accuracy of the current method was analyzed based on current probe performance and circuit parasitic parameter performance (such as parasitic inductance), while the accuracy of voltage method was studied based on coupling capacitance performance and insertion component performance. The resonance effect was further investigated for differential mode noise source impedance extraction. We finally proposed a novel design and our theoretical analysis; simulation and experiment results showed that the conductive EMI noise can be reduced effectively by our …innovative approach. Show more

Keywords: Applied electromagnetic, conductive electromagnetic interference (EMI), noise source impedance extraction, electromagnetic compatibility (EMC)

DOI: 10.3233/JAE-140178

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 3, pp. 347-361, 2015

Authors: Wang, Xiaoguang | Zhang, Xiao

Article Type: Research Article

Abstract: One modeling method of incomplete constraint magnetic levitation system (ICMLS) is investigated in this paper. ANSYS-based simulation of edge effect of an electromagnet is carried out to study on the mechanical properties of electromagnetic force induced by the edge effect, and from the analysis of simulation results, conclusions can be drawn that the edge effect of an electromagnet should not be ignored in the direction of incomplete constraint degree of freedom (DOF) in the ICMLS, and furthermore, a modeling law of the ICMLS is presented. By experiments conducted in the ICMLS prototype, the mathematical dynamics model is developed, and mechanical …properties of the prototype is measured in some specified directions of incomplete constraint DOF and damping term is added in the equation of motion. Finally, the proposed modeling method of the ICMLS prototype is validated by some excitation tests and has references for other similar magnetic levitation systems. Show more

Keywords: Incomplete constraint, magnetic levitation system, dynamics modeling, electromagnet edge effect

DOI: 10.3233/JAE-150012

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 3, pp. 363-373, 2015

Authors: Yang, Fan | Gao, Bing | Chen, Minuyou | Wei, Lin | Peng, Qingjun | Zou, Lifeng

Article Type: Research Article

Abstract: The operation environment of electric power cables undergoes more and more natural damages, such as earthquake, flood which would result in the change of unit capacitance and inductance of power cables, as well as the reactive power. In this paper, a method of ``distributed model'' based on Poynting vector and space-stepping finite difference frequency domain (FDFD) is proposed to calculate the reactive power of power cables. Comparing with the method of ``lumped model'', it can calculate the reactive power of power cables without computing the unit capacitance and inductance which are difficult to get, especially when the cable trench is …fill with ponding, sludge and collapse. Calculation of the reactive power has been carried out in consideration of eccentric and water infiltration cases, and results indicate that ponding environment will lead to a substantial increase of capacitive reactive power. Capacitive reactive power increase with cable eccentricity degree; when cables suffer both water ingress and a 2.5 mm eccentricity degree, the increased capacitive reactive power will reach 51.98%. Show more

Keywords: Poynting vector, FDFD, eccentric cable, water infiltration, reactive power

DOI: 10.3233/JAE-150013

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 3, pp. 375-385, 2015

Authors: Ullah, M. Habib | Mahadi, W.N.L. | Latef, T.A. | Islam, M.T. | Uddin, M.J. | Ahsan, M.R.

Article Type: Research Article

Abstract: The design and prototyping of a dual port planar printed quad band/Ultra wide band (UWB) patch antenna, with octagonal ring shaped metasurface structure (MSS) assimilated at the back to reduce mutual coupling between antenna elements, is presented. The proposed MSS incorporated UWB antenna has been designed and fabricated on a high permittivity (εr = 15) ceramic filled biopolymer based sandwich structured dielectric substrate. Substantial reductions of mutual coupling (S21) between the dual port array elements of the proposed antenna has been achieved by assimilating a 6 × 9 octagonal ring shaped metasurface structure with near zero refractive index (NZRI) in …the ground plane. Measurement results show that the proposed antenna with MSS loading has achieved the reflection co-efficient (S11 <-10 dB) bandwidths of 1.25 (2.25-3.5) GHz, 1 (4-5) GHz, 0.7 (5.9-6.6) GHz and 1.75 (7.7-9.45) GHz. Stable radiation patterns, with gains of 3.18 dBi, 2.96 dBi, 3.34 dBi and 9.61 dBi, have been measured at resonant frequencies of 2.85 GHz, 4.4 GHz, 6.2 GHz and 8.75 GHz. Show more

Keywords: Mutual coupling reduction, octagonal ring metasurface structure, near zero refractive index, dual port antenna, ultra wideband

DOI: 10.3233/JAE-150048

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 3, pp. 387-394, 2015

Authors: Hossain, M.I. | Faruque, M.R.I. | Islam, M.T. | Arshad, H.

Article Type: Research Article

Abstract: A new design and analysis of cellular phone casing based on shielding technique is presented in this study to reduce the EM absorption in the human head. A dual band PIFA is designed to operate at 900 MHz and 1900 MHz GSM frequency bands as an internal handset antenna. The specific absorption rate (SAR) in the human head and total absorbed power by the cell phone user are calculated along with antenna performances. It is found that the SAR in the head is reduced due to the proposed casing considerably for both the lower and upper frequency bands. The …new mobile casing provides 48.2% reduction in the SAR at 900 MHz and 44.8% reduction at 1900 MHz. In addition, the mobile casing improves the radiation efficiency for 6% and 7% in comparison with without casing configuration at the lower and upper GSM frequency bands respectively. Show more

Keywords: Antenna, EM absorption, mobile casing, head model, hand model, SAR

DOI: 10.3233/JAE-150045

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 3, pp. 395-403, 2015

Authors: Patel, Amit | Vala, Alpesh | Mahant, Keyur | Goswami, Riddhi

Article Type: Research Article

Abstract: This paper demonstrates transverse nonplanar resonators consisting of symmetrically placed obstacles (posts which made up of same or different type of materials) coupled into rectangular waveguide. Introducing posts inside a waveguide in proposed structure creates discontinuity and become a cavity resonator. Resonance is created at X band, Ku band and Ka band frequencies are reported. Simulation results demonstrates that resonators's results are matched to free-space as well as having a superior insertion loss and better return loss of conductive posts compare to dielectric posts. Moreover, obstructing the E-field (using conductive posts) compare to the H-field (using dielectric posts) are given …better insertion loss and impedance matching characteristics. However, insertion of amalgamated obstacles into rectangular waveguide generates good transmission and reflection zeros compared to other two topologies at resonant frequencies which are described here. Posts coupled waveguide resonators having high power handling capacity so it can be utilized for Base transceiver station, Satellite Communication, Space applications, sensors as well as the fusion plasma diagnostics system. All the proposed structures are simulated with Ansoft's finite-element High Frequency Structure Simulator (HFSS) tool to demonstrate the characteristics of the resonators using a rectangular waveguide with center frequency of 11.2 GHz for X-band. In addition, the equivalent model of resonator is simulated in ADS (Advance designing system). It is observed that offered topologies are very sensitive to the parameters deviation (Post coupled waveguide resonator performance depends on diameter of conductive post, elevation of post and detachment between posts). Show more

Keywords: Amalgamated posts, PCWR (posts coupled waveguide resonator), cavity resonator, insertion loss, quality factor

DOI: 10.3233/JAE-150049

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 3, pp. 405-415, 2015

Authors: Yang, Wei | Qi, Cong-Hui | Zhao, Zhi-Qin

Article Type: Research Article

Abstract: A novel bi-iterative model is proposed to solve the extra large-scale composite electromagnetic (EM) scattering from an object above a rough surface. For the rough surface scattering, the forward-backward methodology and its modification with under-relaxation iteration method are developed to accelerate the convergence of the iterative physical optics (IPO) and improve its robustness. Meanwhile, the local iteration methodology and the fast far field approximation (FaFFA) in the matrix-vector product are proposed to reduce effectively the computational complexity and further improve the efficiency of the whole iteration process. Hence, this model can greatly reduce the computational costs, including both RAM memory …and CPU time. Show more

Keywords: EM scattering, fast far field approximation, target above rough surface, under-relaxation iteration

DOI: 10.3233/JAE-150055

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 3, pp. 417-425, 2015

Authors: Zhang, Li | Jiao, Yong-Chang | Ni, Tao | Liang, Wei-Long

Article Type: Research Article

Abstract: A wideband circular polarization (CP) printed monopole antenna with coplanar-waveguide (CPW)-fed is presented for wireless communication applications. By employing T-shaped slot in the ground-plane, the impedance bandwidth of the antenna is enlarged, and its wide axial-ratio (AR) bandwidth is realized. The measured results show a -10 dB impedance bandwidth of 75.39% (3.62-8.00 GHz) and an axial ratio (AR) bandwidth of 31.38% (4.81-6.60 GHz), which agree well with the simulated results. The proposed antenna can provide a peak antenna gain of about 1.68 dBi at 5.00 GHz, with gain variations less than 0.81 dB for frequencies within the CP bandwidth.

Keywords: Monopole antenna, wideband antenna, circular polarization (CP)

DOI: 10.3233/JAE-150062

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 3, pp. 427-434, 2015

Authors: Liu, Q.F. | Feng, W.J. | Su, R.K.L.

Article Type: Research Article

Abstract: The fracture properties of an inclined crack through a rhombic thin superconducting strip with transport current are investigated. The flux and current density distributions in the processes of both ascending and descending transport currents are given in clear forms. Adopting the plane strain problem model, the energy release rates (ERRs) of the inclined crack are calculated by the finite element method (FEM). The effects of inclined angle, crack length, maximal thickness and applied maximal transport current on the ERRs are discussed in detail in the process of descending transport current. All the obtained results should be of vital importance for …the application of superconductors. Show more

Keywords: Energy relate rate, inclined crack, rhombic superconducting strip, transport current

DOI: 10.3233/JAE-150066

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 3, pp. 435-442, 2015