The transient backscattering mechanisms of a dipole array with reflector have been investigated from different aspects： time-domain, frequency-domain, and combined time-frequency domain, using 4 × 8 dipole array...The transient backscattering mechanisms of a dipole array with reflector have been investigated from different aspects： time-domain, frequency-domain, and combined time-frequency domain, using 4 × 8 dipole arrays with reflector as an example. The data of scattering from the arrays under the incidence of Gaussian pulses are obtained by finite differential time domain method. The influences of the array structural parameters, incident wave parameters, and incident angles on the waveforms, spectrum, and time-frequency representations of the backscattered fields of the arrays are analysed and conclusions are drawn. From these characteristics and conclusions, it is possible to deduce the array structure inversely from the backscattered field.展开更多
This paper constructs a concentric ellipsoid torso-heart model by boundary element method and investigates the impacts of model structures on the cardiac magnetic fields generated by both equivalent primary source--a ...This paper constructs a concentric ellipsoid torso-heart model by boundary element method and investigates the impacts of model structures on the cardiac magnetic fields generated by both equivalent primary source--a current dipole and volume currents. Then by using the simulated magnetic fields based on torso-heart model as input, the cardiac current sources--an array of current dipoles by optimal constrained linear inverse method are constructed. Next, the current dipole array reconstruction considering boundaries is compared with that in an unbounded homogeneous medium. Furthermore, the influence of random noise on reconstruction is also considered and the reconstructing effect is judged by several reconstructing parameters.展开更多
An equivalent radiation source method is proposed to characterize electromagnetic emission and interference of complex three dimensional integrated circuits（IC） in this paper.The method utilizes amplitude-only near-...An equivalent radiation source method is proposed to characterize electromagnetic emission and interference of complex three dimensional integrated circuits（IC） in this paper.The method utilizes amplitude-only near-field scanning data to reconstruct an equivalent magnetic dipole array,and the differential evolution optimization algorithm is proposed to extract the locations,orientation and moments of those dipoles.By importing the equivalent dipoles model into a 3D full-wave simulator together with the victim circuit model,the electromagnetic interference issues in mixed RF/digital systems can be well predicted.A commercial IC is used to validate the accuracy and efficiency of this proposed method.The coupled power at the victim antenna port calculated by the equivalent radiation source is compared with the measured data.Good consistency is obtained which confirms the validity and efficiency of the method.展开更多
基金Project supported by the Foundations of Beijing Jiaotong Universitythe Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry
文摘The transient backscattering mechanisms of a dipole array with reflector have been investigated from different aspects： time-domain, frequency-domain, and combined time-frequency domain, using 4 × 8 dipole arrays with reflector as an example. The data of scattering from the arrays under the incidence of Gaussian pulses are obtained by finite differential time domain method. The influences of the array structural parameters, incident wave parameters, and incident angles on the waveforms, spectrum, and time-frequency representations of the backscattered fields of the arrays are analysed and conclusions are drawn. From these characteristics and conclusions, it is possible to deduce the array structure inversely from the backscattered field.
基金Project supported by the State Key Development Program for Basic Research of China(Grant No.2006CB601007)the National Natural Science Foundation of China(Grant No.10674006)the National High Technology Research and Development Program of China(Grant No.2007AA03Z238)
文摘This paper constructs a concentric ellipsoid torso-heart model by boundary element method and investigates the impacts of model structures on the cardiac magnetic fields generated by both equivalent primary source--a current dipole and volume currents. Then by using the simulated magnetic fields based on torso-heart model as input, the cardiac current sources--an array of current dipoles by optimal constrained linear inverse method are constructed. Next, the current dipole array reconstruction considering boundaries is compared with that in an unbounded homogeneous medium. Furthermore, the influence of random noise on reconstruction is also considered and the reconstructing effect is judged by several reconstructing parameters.
基金supported by the National Nature Science Foundation of China(No.61274110)
文摘An equivalent radiation source method is proposed to characterize electromagnetic emission and interference of complex three dimensional integrated circuits（IC） in this paper.The method utilizes amplitude-only near-field scanning data to reconstruct an equivalent magnetic dipole array,and the differential evolution optimization algorithm is proposed to extract the locations,orientation and moments of those dipoles.By importing the equivalent dipoles model into a 3D full-wave simulator together with the victim circuit model,the electromagnetic interference issues in mixed RF/digital systems can be well predicted.A commercial IC is used to validate the accuracy and efficiency of this proposed method.The coupled power at the victim antenna port calculated by the equivalent radiation source is compared with the measured data.Good consistency is obtained which confirms the validity and efficiency of the method.
