A Study On 1-D And 2-D Electromagnetic Transmission Characteristic Of EBG Structure

EBG (Electromagnetic Band Gap) structure is a kind of periodic structure that has some special characteristics, such as bandstop, slow wave, and high effective characteristic impedance. It can suppress the propagation of electromagnetic waves of a specified frequency band at a direction. EBG structures have been used widely for design of microwave circuits and antennas.Different method is adopted to analyze different style of EBG structures. FDTD (Finite-Difference Time-Domain) and FEM (Finite Element Method) are adopted in this paper. Up to now, FDTD method has the advantages in electromagnetic simulation, such as computation once in time domain to achieve frequency domain results, and also has better performance in wide band simulation. However, low precise is shortcoming of FDTD method. While FEM adopts adaptive gridding mesh and sub-gridding technology, it is easily to deal with complicate structure and inhomogeneous medium. FEM has the advantages like more accurate simulating results and high computation efficiency. Thus, FEM has a bright engineering prospect.Simulation in this paper by either FDTD or FEM is performed to analyze the transmission characteristics of EBG structures. New method is proposed. Then the simulation results are compared with the theoretic analysis and measured ones.A simple and precise method named equivalent-medium method is proposed to analyze the transmission characteristics of 1-D microstrip EBG structure. The simulation results and the empirical results have a good agreement. The method is fast and more efficient, which is of great significance to design novel filters with small mass, light weight and good performance.