Research On EMC Anechoic Chamber Performance Analysis In Time Domain

Electromagnetic compatibility (EMC) anechoic chambers are key equipments in the EMC research. The characteristicanalysis,prediction and design of EMC chamber by computer simulation are in the highlight at nowdays research works in EMC field. Furthermore, a proper computational model of EMC chamber could provide the foundation of the EMC virtual design and research of electric products. This dissertation investigates the time-domain characteristics and key design problems of EMC chambers. The main works are as follows:1. The lossy pyramid absorber models for time domain analysis are constructed including the affection of electric conductivities which is technically produced in the absorber manufacture. By the use of a Finite Difference Time Domain (FDTD) algorithm, the effects of the absorber arrays with different design parameters on electromagnetic wave are simulated and analyzed.2. For the dispersive properties of absorbers, an new 3D-FDTD formulation, boundary condition and algorithm are presented under considering dispersive permittivity, dispersive magnetic permeability and electric conductivity based on digital processing technique.Therefore, the electromagnetic fields in absorbers with dispersive property can be more accurately investigated under different incident waves.3. In order to give a solution to the electric problems with electrically large scale, such as the simulation to large anechoic chamber, an new Multiresolution Time Domain scheme (MDTD) is presented under considering the lossy and dispersive properties of materials by a wavelet scale function. With the scheme, the characteristics of anechoic chamber have been analyzed and predicted.4. The numerical simulation models of chambers are well constructed. The chamber models include absorbers which have lossy and dispersive properties. Based on the models, Normalized Site Attenuation (NSA) and pure region measurement are analyzed to verify the modified MRTD method proposed in the dissertation.For designing and analizing of the EMC chambers, this dissertation presents a systemic time domain analysis methods for complicated material properties. The operating mechanism ofelectromagnetic waves in absorbers is investigated in depth. The solutions to the material modeling problem for both dispersive permittivity and dispersive magnetic permeability, the large electric problem and the characteristics analysis for chambers with dispersive absorbers are given. It provides an effective analyzing theory and tool for the EMC chamber design and the virtual EMC measurement of electronic and electric products in engineering.