Research On EBG Structures For EMI Suppression

EBG (Electromagnetic Band Gap) structure is a periodic structure with the characteristics of band-stop, slow-wave, and high-impedance. It can prohibit the propagation of the electromagnetic wave in a certain bandwidth range. Being simply made, small size, light weight and ease of integration, it attracts widespread attention and receives in-depth study.The thesis mainly focuses on EBG structures used for electromagnetic interference suppression, including HIS EBG structures used for surface wave suppression and uniplanar EBG structures used for simultaneous switch noise suppression.HIS EBG structures used for surface wave suppression are firstly studied. Ansoft HFSS software which is based on the finite element method is used to simulate the EBG structures. As a typical, mushroom-EBG structure which can be integrated with PCB is analyzed in different methods. On the basis of mushroom-EBG structure, we proposed a novel compact EBG structure. Simulation results show the structure has a winning feature of compactness."United cells method"is applied in the novel structure to broaden its bandwidth. The novel structure is successfully used to reduce surface-wave losses for a double-element microstrip antenna array and a 3.5 dB reduction of mutual coupling is achieved.Different kinds of uniplanar EBG structures are analyzed. According to simulation result of EBG structure which is mentioned above, a novel uniplanar EBG structure is proposed with ultra--wideband suppression of simultaneous switch noise (SSN) from 270 MHz to 15 GHz. The measured results are in good agreement with simulated results. Good signal integrity performance can be obtained by using differential transmission lines.