Cylindrical waveguides without end surfaces can serve as two-dimensional resonant cavities. In such cavities the electromagnetic oscillations corresponding to an eigenfrequency can always be taken as TM or TE modes ev...Cylindrical waveguides without end surfaces can serve as two-dimensional resonant cavities. In such cavities the electromagnetic oscillations corresponding to an eigenfrequency can always be taken as TM or TE modes even when the walls have a finite conductivity and the medium is absorptive. This paper obtains analytic solutions to the field equations when the cylinder has a circular cross section. Some nonperturbative conclusions are drawn from the eigenvalue equation. Approximate analytic results for the resonant frequencies are obtained when the absorption of the medium is small and the walls are good conductors. Stability of the eigen modes is discussed. Similar results for the coaxial line are presented.展开更多
The radiation of a loop antenna embedded in a dissipative medium with complex boundaries isanalyzed by a perturbation method and an efficient fast multiple-integration technique. But theperturbation method can not be ...The radiation of a loop antenna embedded in a dissipative medium with complex boundaries isanalyzed by a perturbation method and an efficient fast multiple-integration technique. But theperturbation method can not be used directly because there is a finite-length metal cylinder in the vicinityof the loop antenna. The prolate ellipsoid equivalence of the metal cylinder is made, then the cylinder maybe removed and the perturbation method is valid. Numerical results indicate that the approach is accurateat low frequencies and stable.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. 10675174)
文摘Cylindrical waveguides without end surfaces can serve as two-dimensional resonant cavities. In such cavities the electromagnetic oscillations corresponding to an eigenfrequency can always be taken as TM or TE modes even when the walls have a finite conductivity and the medium is absorptive. This paper obtains analytic solutions to the field equations when the cylinder has a circular cross section. Some nonperturbative conclusions are drawn from the eigenvalue equation. Approximate analytic results for the resonant frequencies are obtained when the absorption of the medium is small and the walls are good conductors. Stability of the eigen modes is discussed. Similar results for the coaxial line are presented.
文摘The radiation of a loop antenna embedded in a dissipative medium with complex boundaries isanalyzed by a perturbation method and an efficient fast multiple-integration technique. But theperturbation method can not be used directly because there is a finite-length metal cylinder in the vicinityof the loop antenna. The prolate ellipsoid equivalence of the metal cylinder is made, then the cylinder maybe removed and the perturbation method is valid. Numerical results indicate that the approach is accurateat low frequencies and stable.
