International Journal of Applied Electromagnetics and Mechanics - Volume 67, issue 4

Authors: C.R., Lakshmi | Kannadassan, Dhanaraj

Article Type: Research Article

Abstract: This paper reports the demonstration of design and implementation of narrow band band-stop filters using slotted ground resonators. Using coupled-mode resonator theory, the systematic implementation of BSFs are performed to achieve narrow stopband (<25% FBW) with desired stopband isolation. By exchanging the band-pass transfer function polynomials, the BSF design has become straight-forward with these band-stop resonators. Designed and optimized BSFs are fabricated, characterized and analysed as a detailed report. Slotted ground resonators yield compact and scalable BSFs which are potential alternatives for the development of future microwave systems.

Keywords: Slotted ground resonators (SGR), band stop filters (BSF), fractional bandwidth (FBW), coupled resonators

DOI: 10.3233/JAE-210019

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 67, no. 4, pp. 393-407, 2021

Authors: Wang, Tingting | Xu, Lizhong | Xing, Jichun

Article Type: Research Article

Abstract: In this paper, the structural design and driving mechanism of a non-contact piezoelectric motor modulated by electromagnetic force are introduced. The equations of the electromagnetic force and torque of the electromagnetic modulation mechanism for the motor are deduced. Based on the piezoelectric constitutive equation and torque balance equations of the driving system, the equation of the piezoelectric driving torque is also obtained. Using these equations, the influences of the related parameters on the relationship between electromagnetic torque and angle difference between pole and rotor are studied. The influences of the main parameters and signal frequency on piezoelectric driving torques are …analyzed. Based on them, the torque optimization of the motor is completed and the load-carrying ability of the motor is increased by about 50 times. A prototype of the motor is developed. Its output torque is tested and compared with calculated one which illustrates the theoretical model here. Show more

Keywords: Torque, piezoelectric motor, non-contact, modulated by electromagnetic force

DOI: 10.3233/JAE-210043

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 67, no. 4, pp. 409-429, 2021

Authors: Guesmi, Mohamed | Harzallah, Salaheddine | Kouzou, Abdellah

Article Type: Research Article

Abstract: Crack orientation is a vital factor in the behavioral study of fractures, especially the study of crack propagation in structures that are under dynamic or fatigue loading. Indeed, many non-destructive testing (NDT) techniques have been developed recently for the detection of cracks such as the eddy current testing (ECT). However, the crack orientation has not been undertaken into consideration. In this paper, a NDT based on eddy current using 3D finite element modeling, is proposed for the determination of the crack orientation. The idea of this proposed technique benefits from the influences of crack orientation, which can be observed on …the components of eddy current and the related magnetic flux density following the x , y axes, for the estimation of the crack angle orientation based on an interpolation criteria. The obtained results through the presented simulation prove the validity of the proposed technique for the detection of crack angle orientation. Show more

Keywords: Crack orientation, eddy current, non-destructive testing, finite element modeling, stress intensity factor, J-integral

DOI: 10.3233/JAE-210049

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 67, no. 4, pp. 431-451, 2021

Authors: Qing, Li | Miao, Tian | Peng, Gao | Jie, Teng | Bing, Wang | Qing, Tang Bruce | Hong, Wu

Article Type: Research Article

Abstract: Many kinds of physical fields are able to affect biological activity, such as electromagnetic field, magnetic field, scalar wave, magnetic vector potential and so on. Some works investigated a high-penetrating emission (HPE) generated by a LED generator that can affect the conductivity of water and the growth of dry yeast. In this research, the biological effect of the HPE of LED generator on S. cerevisiae was studied. The results showed that this kind of HPE could promote the growth of S. cerevisiae . With the decrease of initial concentration and the extension of exposure time, the growth promoting effect …of HPE increased significantly. When the initial cell concentration was 2 × 102 cell/ml and exposed for 24 h, the number of yeast cells increased by 19.5% compared with the control group. Further studies showed that adenosine triphosphate (ATP) content and the ratio of ATP and adenosine diphosphate (ADP, ATP/ADP ratio) of exposed cells were higher than those of unexposed cells, indicating that exposed cells had higher cell viability and energy status. In addition, the intracellular superoxide (O2 − ) content decreased significantly after the HPE exposed. In this study, the stainless steel box acts as a Faraday cage to shield the electromagnetic field, so the biological effect of the HPE is not produced by the electromagnetic field. Nevertheless, the mechanism of the HPE is still unknown and needs further research. This is the first report on the effect of HPE on mitochondrial parameters, contributing to further study on HPE and revealing potential for future medical applications. Show more

Keywords: HPE, Saccharomyces cerevisiae , growth, superoxide, ATP/ADP ratio

DOI: 10.3233/JAE-210054

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 67, no. 4, pp. 453-460, 2021

Authors: Park, Sohyun | Lee, Jaejoon | Lee, Jaewook

Article Type: Research Article

Abstract: This paper presents a multi-material topology optimization for the design of permanent magnet synchronous motors (PMSMs). Specifically, structural shapes of permanent magnet (PM) and iron core in a PMSM rotor are simultaneously designed together with the orientation of PM magnetization. For a co-design of PM and iron core, relative permeability and residual magnetic flux density are interpolated by the three-field density approach based on the Helmholtz filtering and regularized Heaviside step function. Here, the Helmholtz filtering aims to attain smooth border in design results, and the Heaviside function enables us to acquire a clear border (i.e. zero-one design) without intermediate …densities. The optimization goal is set as maximizing the average torque of PMSMs. The average torque is calculated by Maxwell stress tensor (MST) method considering a maximum torque per ampere (MTPA) control. To validate the effectiveness of the proposed multi-material topology optimization approach, a PMSM rotor with 4 poles and 12 slots is designed. In addition, design results at various settings of input current amplitude and PM strength are compared and discussed. When the input current is stronger than the PM strength, rotor PM and iron core are designed for utilizing both PM and reluctance torque components like V-shape interior PMSMs. On the other hand, in the case of stronger PM strength, PM is designed near the air-gap, which utilizes only PM torque component like surface PMSMs. Show more

Keywords: Topology optimization, permanent magnet synchronous motors (PMSMs), permanent magnets (PMs), iron, finite element methods

DOI: 10.3233/JAE-210062

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 67, no. 4, pp. 461-472, 2021

Authors: Deng, Licheng | Yang, Lei | Xue, Zhicheng | Ren, Qingying | Wang, Debo

Article Type: Research Article

Abstract: An omnidirectional acoustic energy harvester (AEH) based on six Helmholtz resonators is proposed in this work. Compared with the previous structure, the insufficiency of the directionality and conversion efficiency of energy collection can be effectively improved due to the coupling of six resonators. Based on the distributed parameter model, the relationship of the electrical output, the input frequency with the structure size is obtained. The simulation results show that the maximum output voltage is 70.95 mV at the resonant frequency of 35 kHz. When the external load resistance is 14 kΩ, the maximum output power is 0.45 μW. Moreover, the energy conversion efficiency of …this omnidirectional AEH can reach 23%, which is improved greatly compared with the traditional structure. Therefore, this AEH will have a wide range of application prospects in medical implantation equipment and other fields. Show more

Keywords: AEH, Helmholtz resonators, the output power, conversion efficiency

DOI: 10.3233/JAE-210076

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 67, no. 4, pp. 473-485, 2021

Authors: Kumaran, Nithila | Arunachalam, Kavitha

Article Type: Research Article

Abstract: An electrically thin (0.024𝜆0 ) high-impedance surface (HIS) on a magneto-dielectric nanocomposite (NC) is presented as an external shield for wideband absorption of mobile phone radiation. Characterization of the NC and numerical design and analysis of the miniaturized HIS unit cell on NC (0.088𝜆0  × 0.088𝜆0 ) are presented over 0.85–6 GHz, where 𝜆0 is the free space wavelength at the absorber resonant frequency. The absorber performance is assessed using a mobile phone handset at 0.9 and 1.8 GHz Global System for Mobile Communications (GSM) frequencies and 2.4 GHz Wireless Fidelity (WiFi) frequency. Handset specific absorption rate (SAR) measurements with …the absorber recorded in head phantom indicated 83, 48 and 71% reduction in peak SAR at 0.9, 1.8 and 2.4 GHz, respectively without significantly affecting the handset radiation characteristics in free space. Simulation results of human head model with the hand showed SAR reduction of 69, 24 and 65% at 0.9, 1.8 and 2.4 GHz, respectively for 1 g SAR. It is concluded that the proposed absorber could be used to lower handset SAR levels and shield mobile communication signals over 0.85–6 GHz. Show more

Keywords: EM shielding, high impedance surface, mobile phone, nanocomposite, SAR

DOI: 10.3233/JAE-210092

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 67, no. 4, pp. 487-506, 2021

Authors: Akdoğan, Hilmi | Tabatadze, Vasil | Karaçuha, Kamil | Yaldiz, Ercan

Article Type: Research Article

Abstract: The study investigates basically, the electric field distribution in a semi-closed region. Specifically, the present work focuses on the electromagnetic wave diffraction at 3.5 GHz in the vicinity of a car where two humans are located inside. The car is modeled as the perfect electric conducting object whereas the human bodies are assumed to be homogeneous lossy dielectrics. To obtain field distributions for different sceneries, the Method of Auxiliary Sources (MAS) is employed. To achieve this goal, the auxiliary sources due to each obstacle are distributed over the corresponding surface element. In the present study, two main different scenarios are considered. …One or two cellphones as the source of electromagnetic waves are considered. These cellphones are operating at the proposed 5G frequency band in the European Zone. In this frequency range, the resonances are observed at 3.5 GHz which is in the range of a planned 5G communication frequency band. The present study aims to obtain quantitative and qualitative results for a better understanding of 5G healthy issues. Therefore, as a frontier study, the specific absorption rate (SAR) values are examined for the first time to answer some important questions related to 5G. For such a scenario, MAS is a very efficient, fast, and trustworthy approach to obtain field distribution at semi-closed regions. Show more

Keywords: Car, computation electromagnetics, electromagnetic diffraction, human body, MAS

DOI: 10.3233/JAE-210035

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 67, no. 4, pp. 507-520, 2021