Electromagnetic Field Coupling to Transmission Lines Inside Rectangular Resonators

In this paper the current inside a cavity, which is induced by lumped and distributed sources, is calculated. The current is obtained analytically (Green’s function method) and numerically (MoM – and MLFMM – method). A long, parallel wire is chosen that connects two opposite walls of a rectangular resonator. Since the conductor conserves the translational symmetry of the resonator in one direction (z-direction), the current and the total exciting electrical field can be derived from Fourier series formulations. The obtained results clearly show the influence of the resonator on the induced current. Resonance peaks of the resonator, which do not arise in usual EMC laboratory tests, occur in the current spectra. The numerical results agree very well with the analytical ones, however, the results are obtained much faster using the analytical formulae by a factor of one thousand. _________________________________________________________________________ This work was sponsored by the German Research Foundation (DFG) under the contract number:NI 633/5-1