International Journal of Applied Electromagnetics and Mechanics - Volume 50, issue 2

Authors: Tang, Z.-M. | Huang, K.-M. | Liao, Y.-H. | Hong, T. | Zhu, H.-C.

Article Type: Research Article

Abstract: Microwave heating has been widely used and the heating uniformity is related to the characteristics of electric field. In this paper, we investigate the stability of electric field in a multimode microwave cavity by analyzing the spectrum and the condition number of integral equation. Results show that the stability of the electric field is mainly dependent on microwave frequency, the permittivity of heating object and cavity geometrical parameters. Particularly, when the heating object has a low loss factor, the electric field is generally unstable. Namely, a tiny shift of the parameters mentioned above will result in dramatic changes of electric …field distribution. Besides, the instability of the electric field increases with the lower loss, the higher microwave frequency or the larger permittivity of the heating object. Show more

Keywords: Electric field stability, multimode microwave heating cavity, spectrum, condition number

DOI: 10.3233/JAE-150098

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 2, pp. 321-330, 2016

Authors: Zhang, Zhi-Ya | Yang, Long | Zuo, Shao-Li | Huang, Peng | Fu, Guang

Article Type: Research Article

Abstract: A novel miniature circularly polarized (CP) microstrip antenna with beamwidth improvement is proposed. The approaches employed in this design to improve the beamwidth performance are to utilize four vertical conductive walls around the radiation patch and to locate four metal isosceles triangle patches at the top of the radiation patch. Four slots are etched along the diagonals of radiation patch with the ground plane folded to achieve the miniaturization of the antenna by extending the current path. In addition, by introducing an electromagnetic coupling feed and a compact broadband phase shifting network, the proposed antenna can achieve a wide impedance …bandwidth for VSWR ≤ 1.5 ranging from 1.1 to 1.8 GHz (about 48%) and a 3-dB AR bandwidth from 1.1 to 1.7 GHz. Moreover, the 3-dB beamwidth is over 100° in this operating frequency range. In this way, the antenna size is reduced to 0.42 λ 0 × 0.42 λ 0 × 0.16 λ 0 , where λ 0 is the wavelength at the center frequency in the free space. Show more

Keywords: Circularly polarized, wide beamwidth, impedance bandwidth

DOI: 10.3233/JAE-150111

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 2, pp. 331-337, 2016

Authors: Zhang, Mengqi | Tseng, King-Jet

Article Type: Research Article

Abstract: A lumped magnetic equivalent circuit model is proposed to predict the electromagnetic performance of an interior permanent magnetic machine under stator inter-turn winding short-circuit fault. The model design takes into account iron core magnetic saturation, magnetic cross-coupling due to rotor saliency, and airgap magnetic circuit optimization. By comparing with finite element method analysis, the model presents appealing accuracy but much less required computation time in predicting machine flux distribution, winding inductance, and electromagnetic torque. These features prove the usefulness to promote MEC model as a convenient tool for machine performance prediction and fault analysis.

Keywords: Finite element method, magnetic circuit, machine perfromance prediciton, stator winding short-circuit

DOI: 10.3233/JAE-150112

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 2, pp. 339-352, 2016

Authors: Jilani, Muhammad Taha | Wen, Wong Peng | Rehman, Muhammad Zaka Ur | Khan, Abid Muhammad | Cheong, Lee Yen

Article Type: Research Article

Abstract: This paper presents a microwave sensor for the non-destructive dielectric characterization of biological tissues. The proposed sensor is based on microstrip ring-resonator, which is utilized for quality evaluation of meat at 1 GHz frequency. The obtained results from measurement and simulation are in good agreement for the studied meat samples. Using numerical formulations, dielectric constant of meat samples is extracted and then compared with those acquired by well-established and commercially available coaxial-probe method. Negligible difference is observed in obtained data, the maximum discrepancy is about 6% only. Findings of this study provide new possibilities to employ microwave circuits for non-destructive …evaluation of dielectric materials. Show more

Keywords: Dielectric constant, dielectric properties, effective permittivity, microstrip ring resonator, meat quality, dielectric spectroscopy

DOI: 10.3233/JAE-150114

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 2, pp. 353-363, 2016

Article Type: Correction

DOI: 10.3233/JAE-2025

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 50, no. 2, pp. 365-365, 2016