Application Of Dyadic Green's Function To Analysis For Field Of Anechoic Chamber

Anechoic chamber is the primary test site of electromagnetic radiation measurement, also the important facility for antenna and wave propagation research. This paper presents an original Dyadic Green's Function (DGF) formulation to accommodate the electromagnetic environment in anechoic chamber. Tests are carried out to testify its merits.Firstly, chapt. 1 traces down the up-date development of anechoic chamber with regards to the characteristics requirements and international standards concerned, including two evaluation tests for anechoic chamber, Normalized Site Attenuation (NSA) test and field homogeneity test, the Site Reference (SR) method, and uncertainty.In chapt.2, virtual image source is constructed. Reflective coefficients are introduced into the integration of Green's function to calculate the field in chamber, collecting all influence from the absorbers and the metal ground.In chapt.3, the DGF formulation is improved to adapt to the scattering field from finite periodic array structures.Chap. 4 investigates the reflective character of absorbers with different structures and materials in HFSS software. The absorbers include ferrite tile and pyramid. The simulation results are proved credible when compared with other research concerned.In Chap. 5, the diagram is carried out to calculate the electrical field in EMC chamber. In virtual field homogeneity test, chamber performance is evaluated with regard to different set-ups.The validation work is carried out in EMC chamber of BJTU for both field homogeneity test and site attenuation test, with the simulations employing the reflection coefficients from arch method.For field homogeneity evaluation, the simulation use both new DGF and Ray tracing methods. The SR method is chosen in simulation for site attenuation. The result predicts correctly the resonant frequency points.There are some creative points in this paper:1. It is deduced the general solution for electromagnetic wave equation in the form of DGF integration with the help of mathematical techniques. The new formulation is concise to indicate the relation between the equivalent current sources on the boundary and the scattering field (in Chapt.2). 2. It extends the image theory from Perfect Electrical Condition (PEC) to dielectric materials, elaborating a concept as virtual image current source. New DGF formulation for upper space of any material plane is presented, with the boundary condition satisfied consistently (in Chapt.2).3. The Floquet wave method is employed for phase shift to cope with the scattering field of periodic structures in large anechoic chamber (in Chapt.3).4. The walls of periodic absorbers are smoothed up to be virtual surface in simulation (in Chapt.5).5. The consistency of SR method and traditional NSA is discussed (in Chapt.1). The simulation employs SR, whereas the practical test employs NSA. It makes comparison between them effective and reliable (in Chapt.5).6. Antenna pattern of dipole of horizontal polarization is deduced (in Chapt.5).