International Journal of Applied Electromagnetics and Mechanics - Volume 50, issue 1

Authors: Islam, Sikder Sunbeam | Faruque, Mohammad Rashed Iqbal | Islam, Mohammad Tariqul

Article Type: Research Article

Abstract: The paper reveals a near zero refractive index (NZRI) property based metamaterial unit cell for electromagnetic cloaking operation. The metamaterial unit cell displays resonance in the frequency of 8.29 GHz and exhibits near zero refractive index property there. The metamaterial was then utilized in designing a single layer rectangular cloaking device. The rectangular cloaking device hides a cylindrical metal object in the C-band region where almost zero scattering cross section is achieved for the object. The metamaterial also exhibits NZRI property there. The commercially available CST Microwave Studio simulation software, was utilized to obtain all the reflection and transmission parameters …of the unit cell and the cloak. The experimental results were presented as well for both of the metamaterial and the cloak. It was also revealed that the cloak was object size independent in the certain region of C-band. This is a promising design in the electromagnetic paradigm for the rectangular and C-band cloaking operation. Show more

Keywords: Cloak, metamaterial, NZRI

DOI: 10.3233/JAE-150086

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 1, pp. 145-153, 2016

Authors: Jamel, Ben Romdhan Hajri | Hrizi, Hafedh | Sboui, Noureddine

Article Type: Research Article

Abstract: This paper introduces a new formulation of the iterative wave method to study the DGS `Defected Ground Structure' technique applied to the SIW `Substrate Integrated Waveguide' technology. This makes possible the analysis of arbitrary forms of the ground and circuit planes and the {non-conventional} metallic via holes configuration. The study is based on the recursive relationship of longitudinal reflected and incident waves in both spatial and spectral domains. The unconditional stability and the convergence of the method were well verified. In fact, we will validate the proposed approach by the analysis of a SIW filter with folded DGS. The numerical …results are in good agreement with those obtained by the HFSS software `High-Frequency Structure Simulator'. Moreover, the presented method shows a considerable reduction in the required computational resources, which proves the high effectiveness of our method. Show more

Keywords: SIW circuits, defected ground structure technique, iterative wave method

DOI: 10.3233/JAE-150088

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 1, pp. 155-166, 2016

Authors: Hajima, Kohei | Yamashita, Maki | Honda, Takashi

Article Type: Research Article

Abstract: This article provides a novel magnetic actuator suitable for brush cytology using capsule endoscopy. Its space-saving mechanism consisting of a brush-tipped elastic wire coupled with a rotatable permanent magnet can be easily assembled in a swallowable capsule. When external magnetic fields are applied, the brush projects outwards with rotation of the magnet, and then collects cells from gastrointestinal tract. The distinctive feature of the proposed actuator is that it can perform four different actuations including projection/pullback/scrape modes for the brush and a rotation mode for the capsule body. Each actuation mode can be selected by the direction of the external …magnetic fields. This study has verified that each mode can exhibit the desired performance and determined its driving conditions. Furthermore, an additional small magnet attached to the brush tip has been found to enhance the performance of the scrape mode. The results obtained in this study suggested that the proposed actuator should be a hopeful candidate for cytological diagnosis with capsule endoscopy. Show more

Keywords: Brush cytology, capsule endoscope, external magnetic field, magnetic torque, permanent magnet

DOI: 10.3233/JAE-150101

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 1, pp. 167-176, 2016

Authors: Gao, Hui | Song, Wei

Article Type: Research Article

Abstract: The vibration matrix equation of a maglev flywheel because of existing unbalance force is established in this paper to study the unbalance vibration problem. The generalized dynamic stiffness is introduced to obtain the analytical solutions for the vibration equation. The unbalance vibration kinds and corresponding compensation strategies are analyzed according to the analytical solutions, including free vibration and unbalance vibration. To verify the correctness of the analysis result, a simulation model is created of the maglev flywheel system, and the experiment results are given when the flywheel at different rotational frequencies. The simulation and experiment results show that the analytical …solutions and corresponding vibration compensation analyses are effective. Show more

Keywords: Maglev flywheel, mechanical model, unbalance vibration, generalized dynamic stiffness, unbalance compensation

DOI: 10.3233/JAE-150106

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 1, pp. 177-187, 2016

Authors: Sun, Liangwei | Pi, Xitian | Liu, Hongying | Li, Jingcan

Article Type: Research Article

Abstract: As the core component of a precision power operation system for Neurosurgery, medical micro-motors need to have characteristics of high reliability, high speed, high precision, low temperature rise and capability of repeated autoclave sterilization. Therefore, high requirements of design and manufacture are put forward. In view of the above, a super-high speed micro motor with a micro flow channel auxiliary cooling system was proposed in this paper. We used Ansoft to analyze the magnetic field distribution of the motor and operating performances at rated speed, and calculate the motor loss and motor temperature distribution. The results showed that the motor …speed could reach 89000 Rpm in stable operation and the output power was 60 W. The temperature rise of the rotor and stator core was very low, when the temperature of the liquid coolant in cooling system was 20°C, which could efficiently prolong load working hours. This research provided a new idea for the design of a super-high speed micro-motor utilized in neurosurgical power operation system. Show more

Keywords: Super-high speed medical motor, structure design, cooling system, electromagnetic field analysis, temperature field

DOI: 10.3233/JAE-150109

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 1, pp. 189-200, 2016

Authors: Ma, Bo | Yang, Xiao-Ming | Li, Tian-Qian | Chen, Hong-Yuan | He, Hang | Chen, Yuan-Wen | Lin, Ao | Chen, Jiao | Wang, Bang-Ji

Article Type: Research Article

Abstract: This paper presents a novel multiple splits octagon-shaped metamaterial which exhibits double left-handed frequency bands roughly from 9.25 GHz to 9.68 GHz and from 15.28 GHz to 15.36 GHz derived from the transmission characteristics by homogenization retrieval method. Two conventional microstrip patch antennas whose resonance frequency bands are located at the first left-handed frequency band and the second one respectively are designed to further investigate the influence by loading the proposed metamaterial as its superstrate. HFSS simulation numerical results indicate that the far field radiation directivity half-power bandwidth(HPBW) of the E-plane and H-plane have reduced by 64%, 63.7% and 59.4%, …59%, and the maximal gain increases from 8.251 dB to 11.024 dB and from 8.5432 dB to 11.9653 dB respectively after loading with the multiple splits octagonal metamaterial superstrate. Show more

Keywords: Octagon metamaterial, gain, directivity, microstrip antenna, double frequency bands

DOI: 10.3233/JAE-150110

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 1, pp. 201-213, 2016