Title :
Shifted-frequency internal equivalence
Author_Institution :
Dept. of Electr. & Electron. Eng., Hacettepe Univ., Ankara, Turkey
fDate :
1/1/1998 12:00:00 AM
Abstract :
The shifted frequency internal equivalence (SFIE) theorem involving inhomogeneous regions is introduced and proven. For a lossless inhomogeneous region using a vector Green´s theorem and potential formulation, it is shown that the frequency-domain electromagnetic field at frequency ω inside the region can be obtained using a set of equivalent volume and surface currents radiating in free space and at the different frequency ω0. The equivalent currents thus obtained are functions of the two frequencies, electric- and magnetic-volume-type sources of the original problem, material parameters, and the original field phasors at ω, and they only exist inside the region and on its boundary. A direct application of this equivalence is that it can be used to construct an internal equivalence at a shifted frequency for electromagnetic scattering problems if data are needed in a band of frequency. ω0 can be kept constant while the incident field frequency changes and, as a result, full computation of fields at each different frequency for volume-type equivalent sources can be avoided
Keywords :
Green´s function methods; Maxwell equations; electromagnetic wave scattering; frequency-domain analysis; EM scattering problems; equivalent surface currents; equivalent volume currents; frequency-domain EM field; inhomogeneous regions; potential formulation; shifted frequency internal equivalence theorem; vector Green theorem; Electric potential; Electromagnetic analysis; Electromagnetic fields; Electromagnetic scattering; Frequency domain analysis; Magnetic domains; Magnetic materials; Nonhomogeneous media; Nonuniform electric fields; Wave functions;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on