The EBG Applications To The Design Of Microstrip Filters

Yablonovitch and Jhon separately put forward that periodic dielectric structures affect propagation of light in 1987, they bring forward respectively photonic crystal conception. Photonic crystals are a dielectric structure periodic array in another dielectric structure, it is a man-made material. The dielectric's refractive index periodic change in photonic crystal can affect propagation of light, thus very like periodic field in semiconductor affects electrons. In photonic crystals, due to dielectric constant variety, there is a periodic field like semiconductor, when dielectric constant change with a large range, and the period of change is assimilate to wavelength of light, the scatter of bragg leads a band gap. That is a PBG (Photonic Band Gap), he exist of band gap is difficult in light wave range, but it is easy to realize in microwave range. Photonic crystals are named EBG (Electronmagnetic Band Gap) in microwave range. Because the conditions of realize are easy, so many EBG structures are proposed. People think much of EBG, a lot of filters are made base on EBG, especially realizing EBG configuration in microstrip. It integrates the merits of simple fabrication, compact topology and easy integration, so they can be widely used in MM1C.This paper proposes some filters based on micostrip line, they possess a compact configuration and simple fabrication, so they are easy to use in MM1C. The simulations through HFSS show good performance, they have latently merits in late future.