To predict the radiated emission (RE) from AC motors in driver systems under the CISPR 25 standard, this paper proposes a method to estimate the radiation pattern of the stator winding by using antenna array theory. T...
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ISBN:
(纸本)9781509014415
To predict the radiated emission (RE) from AC motors in driver systems under the CISPR 25 standard, this paper proposes a method to estimate the radiation pattern of the stator winding by using antenna array theory. The availability of applying the proposed method is ensured by identifying the radiation region boundaries of the winding structure of a reference motor. The array model of the stator winding can be constructed by magnetic vector potentials from the circular array of axial and end-winding current elements. The calculated patterns, which are excited by the balanced three-phase harmonics at the resonance frequency, show that the radiation becomes significant when the harmonic number is not a multiple of three. Also, we can find that the radiation from the end-winding currents is dominant. Since the estimated radiation patterns are fairly correlated with 3D full-wave simulation results, the proposed method is expected to be used for the prediction of the RE from any stator winding configuration.
To predict the radiated emission (RE) from AC motors in driver systems under the CISPR 25 standard, this paper proposes a method to estimate the radiation pattern of the stator winding by using antenna array theory. T...
详细信息
ISBN:
(纸本)9781509014439
To predict the radiated emission (RE) from AC motors in driver systems under the CISPR 25 standard, this paper proposes a method to estimate the radiation pattern of the stator winding by using antenna array theory. The availability of applying the proposed method is ensured by identifying the radiation region boundaries of the winding structure of a reference motor. The array model of the stator winding can be constructed by magnetic vector potentials from the circular array of axial and end-winding current elements. The calculated patterns, which are excited by the balanced three-phase harmonics at the resonance frequency, show that the radiation becomes significant when the harmonic number is not a multiple of three. Also, we can find that the radiation from the end-winding currents is dominant. Since the estimated radiation patterns are fairly correlated with 3D full-wave simulation results, the proposed method is expected to be used for the prediction of the RE from any stator winding configuration.
This paper compares two basic methods for analysis of the radiation performance of reflectarrayantennas. Two different approaches - arraytheory and aperture field - are first described, and numerical results are the...
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This paper compares two basic methods for analysis of the radiation performance of reflectarrayantennas. Two different approaches - arraytheory and aperture field - are first described, and numerical results are then presented for various reflectarray configurations. The advantages and limitations for each method are discussed, and the numerical results are compared with each other, showing very good agreement. Comparison with full-wave simulations showed that these approaches are time-efficient methods that can accurately calculate the reflectarrayantenna's pattern shape, main-beam direction, beamwidth, and sidelobe and cross-polarization levels. As such, these methods can be efficient tools for antenna engineers for designing and analyzing reflectarrayantennas.
An infinite planar array of controlled elements in the form of overlapped subarrays excited through a multiport circuit is considered. It is analytically shown that the contour element (subarray) pattern with an ideal...
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An infinite planar array of controlled elements in the form of overlapped subarrays excited through a multiport circuit is considered. It is analytically shown that the contour element (subarray) pattern with an ideal contour shape corresponding to the absence of backward mutual coupling and, as a consequence, to the 100% element efficiency can be exactly formed at a definite amplitude distribution over the densely arranged small ideal subarray radiators in spite of the fact that each such a radiator in the subarray has low efficiency caused by the presence of backward mutual coupling. If the small ideal radiators are controlled directly (without the multiport circuit), the contour pattern can be formed with 100 % array efficiency for any shape of the contour. If the radiators are not ideal, then the efficiency of the array shaping the contour pattern is determined by averaging the mismatch efficiency of the uniformly excited array scanning over the region bounded by the contour pattern.
This paper presents the analysis of all adaptive antenna that is formed of a dipole antenna above a ground plane in the presence of electromagnetic band gap (EBG) metallic structures. Electromagnetic simulations are p...
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This paper presents the analysis of all adaptive antenna that is formed of a dipole antenna above a ground plane in the presence of electromagnetic band gap (EBG) metallic structures. Electromagnetic simulations are performed using the method of moments (MoM) and the obtained results show a good concordance with those that call be determined when using antenna-arraytheory. (C) 2005 Wiley Periodicals, Inc.
An electromagnetic scattering model for soybean canopy is presented in this paper. For the inter-plant structure, we propose a semi-deterministic description using the antenna array theory to account for the prevailin...
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ISBN:
(纸本)9780780395091
An electromagnetic scattering model for soybean canopy is presented in this paper. For the inter-plant structure, we propose a semi-deterministic description using the antenna array theory to account for the prevailing agriculture practice of soybean. For the underlying rough surface contribution, we employ a recently developed statistical multiple scattering model. For single plant scattering, we adopt the conventional decomposition of the scattering mechanisms. However, in dealing with the ground bounce scattering mechanisms, we use an approach to calculate the roughness modified Fresnel reflection coefficients similar to that of Rodriguez. To validate this proposed model, a comparison is made between the theoretical predictions and polarimetric backscattering measurements. The results show very good agreements between the two and thus clearly demonstrate the validity of this model.
This paper outlines basic antenna array theory with major emphasis on pattern analysis and synthesis for periodic linear and planar arrays, phased arrays, and conformal arrays. Extension is made to synthesis technique...
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This paper outlines basic antenna array theory with major emphasis on pattern analysis and synthesis for periodic linear and planar arrays, phased arrays, and conformal arrays. Extension is made to synthesis techniques which use computer algorithms. These include arbitrary side lobe control, shaped beams, and phase-only null steering. The subjects of random errors and phased array quantization errors are outlined.
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