Study Of Generalized Resonance In Electromagnetic Scattering By Multiple Conductors

Analysis of scattered near field of complex conducting objects is important for Electromagnetic Compatibility (EMC) design. The study on electromagnetic scattering by single conductor is often reported in many literatures, while the study on multiple conductors is less. The generalized resonance occurring in scattering by multiple conducting objects has special important significance on EMC, which had not been reported in any literature. The generalized resonance is discussed comprehensively in this paper. The author main contributions are as follows: 1. The scattering by cubes, spheres and wire structures are treated based on method of moment (MoM) in frequency domain and time domain. A block iterative method to reduce the computation costs is used to solve the matrix equation led by MoM. For some scattering system, the scattered field is much stronger at some frequency than at other frequencies, which we call as generalized resonance. The effects of dimensions of scattering system on generalized resonance are discussed. The generalized resonance is led by mutual coupling effect between these scatters and the resonance frequency is determined by their sizes and positions , while it is independent of excitation. 2. The analysis of scattering by two wires is presented utilizing transmission line theory. The transmission line theory is extent to multiple wires scattering by current-decomposed. 3. The generalized resonance occurring in wire scattering can be explained by open transmission line cavity. The effect of generalized resonance can be avoided by changing the length of wires. 4. The scattering system of multiple conducting objects is a resonator consisting of several short and open planes. The model analysis of generalized resonance is given on the basis of microwave resonator and optic open resonator theory. The resonance wavelength of generalized resonance is determined by a new expression, which can be used in microwave resonator and optic open resonator. By this expression, the regularity of generalized resonance is well explained and the effect of generalized resonance can be avoided in EMC design. 5. A two-dimensional physical model is established to study radiation pattern of base station antennas mounted on a conducting cylinder in horizontal plane. The simple model reduces the computation costs and is convenieut for treating mounting cylinder with arbitrary shape.