A recursive algorithm is adopted for the computation of dyadic Green＇s functions in three-dimensional stratified uniaxial anisotropic media with arbitrary number of layers. Three linear equation groups for computing ...A recursive algorithm is adopted for the computation of dyadic Green＇s functions in three-dimensional stratified uniaxial anisotropic media with arbitrary number of layers. Three linear equation groups for computing the coefficients of the Sommerfeld integrals are obtained according to the continuity condition of electric and magnetic fields across the interface between different layers, which are in correspondence with the TM wave produced by a vertical unit electric dipole and the TE or TM wave produced by a horizontal unit electric dipole, respectively. All the linear equation groups can be solved via the recursive algorithm. The dyadic Green＇s functions with source point and field point being in any layer can be conveniently obtained by merely changing the position of the elements within the source term of the linear equation groups. The problem of singularities occurring in the Sommerfeld integrals is efficiently solved by deforming the integration path in the complex plane. The expression of the dyadic Green＇s functions provided by this paper is terse in form and is easy to be programmed, and it does not overflow. Theoretical analysis and numerical examples show the accuracy and effectivity of the algorithm.展开更多
Based on the solutions of the Green＇s function for a saturated porous medium obtained by the authors, and using transformation of axisymmetric coordinates, Sommerfeld integrals and superposition of the influence fiel...Based on the solutions of the Green＇s function for a saturated porous medium obtained by the authors, and using transformation of axisymmetric coordinates, Sommerfeld integrals and superposition of the influence field on a free surface, the authors have obtained displacement solutions of a saturated porous medium subjected to a torsional force in a half-space. The relationship curves of the displacement solutions and various parameters （permeability, frequency, etc.） under action of a unit of torque are also given in this paper. The results are consistent with previous Reissner＇s solutions, where a two-phase medium decays to a single-phase medium. The solution is useful in solving relevant dynamic problems of a two- phase saturated medium in engineering.展开更多
A broadband microstrip patch antenna was analyzed and designed.Full wave analysis method(FWAM) was employed to show that a stacked microstrip dual patch antenna(SMDPA) might have a much wider bandwidth than that of ...A broadband microstrip patch antenna was analyzed and designed.Full wave analysis method(FWAM) was employed to show that a stacked microstrip dual patch antenna(SMDPA) might have a much wider bandwidth than that of the ordinanry uni patch one.By means of discrete complex image theory(DCIT),the Sommerfeld integrals (SI) involved were accurately calculated at a speed several hundred times faster than numerical integration method(NIM).The feeding structure of the SMDPA was then improved and the bandwidth was extended to about 22% or more for voltage standing wave ratio (VSWR)s≤2 Finally,a matching network was constructed to obtain a bandwidth of about 25% for s≤1.5.展开更多
文摘A recursive algorithm is adopted for the computation of dyadic Green＇s functions in three-dimensional stratified uniaxial anisotropic media with arbitrary number of layers. Three linear equation groups for computing the coefficients of the Sommerfeld integrals are obtained according to the continuity condition of electric and magnetic fields across the interface between different layers, which are in correspondence with the TM wave produced by a vertical unit electric dipole and the TE or TM wave produced by a horizontal unit electric dipole, respectively. All the linear equation groups can be solved via the recursive algorithm. The dyadic Green＇s functions with source point and field point being in any layer can be conveniently obtained by merely changing the position of the elements within the source term of the linear equation groups. The problem of singularities occurring in the Sommerfeld integrals is efficiently solved by deforming the integration path in the complex plane. The expression of the dyadic Green＇s functions provided by this paper is terse in form and is easy to be programmed, and it does not overflow. Theoretical analysis and numerical examples show the accuracy and effectivity of the algorithm.
基金National Natural Science Foundation of China Under Grant No.11172268
文摘Based on the solutions of the Green＇s function for a saturated porous medium obtained by the authors, and using transformation of axisymmetric coordinates, Sommerfeld integrals and superposition of the influence field on a free surface, the authors have obtained displacement solutions of a saturated porous medium subjected to a torsional force in a half-space. The relationship curves of the displacement solutions and various parameters （permeability, frequency, etc.） under action of a unit of torque are also given in this paper. The results are consistent with previous Reissner＇s solutions, where a two-phase medium decays to a single-phase medium. The solution is useful in solving relevant dynamic problems of a two- phase saturated medium in engineering.
文摘A broadband microstrip patch antenna was analyzed and designed.Full wave analysis method(FWAM) was employed to show that a stacked microstrip dual patch antenna(SMDPA) might have a much wider bandwidth than that of the ordinanry uni patch one.By means of discrete complex image theory(DCIT),the Sommerfeld integrals (SI) involved were accurately calculated at a speed several hundred times faster than numerical integration method(NIM).The feeding structure of the SMDPA was then improved and the bandwidth was extended to about 22% or more for voltage standing wave ratio (VSWR)s≤2 Finally,a matching network was constructed to obtain a bandwidth of about 25% for s≤1.5.
