Research On Filter And Antenna Based On EBG Structure

Electromagnetic Band Gap(EBG)is an artificial magnetic conductor(AMC)structure with surface wave band gap characteristics and in-phase reflection characteristics.With the deepening of the research on the electromagnetic band gap structure,the research focus on the electromagnetic band gap structure has shifted to the combination of the EBG structure and the antenna,using the EBG structure to design filters and the intersection of multi-disciplinary and multi-field.The theory and band gap characteristics of the EBG structure are introduced in this paper,and then studied a miniaturized EBG structure.Finally,the EBG structure is combined with a filter and an antenna,and the application of the new structure in the filter and antenna is studied.Main tasks as follows:(1)The basic principle and equivalent circuit theory of mushroom-type EBG(Mushroom-Type EBG,MT-EBG)structure and improved structure based on MT-EBG are studied,and a Dual-Arms Symmetrical EBG structure is designed based on this theory.Dispersion curve method was used to test the dispersion chart of DAS-EBG structure.Later,the size of the EBG structure was tested using the truncated micro strip line method.The results show that the DAS-EBG structure is approximately 20%smaller than the traditional MT-EBG structure.Moreover,the DAS-EBG structure has multi-band characteristics,with band gaps of 4.0-4.94 GHz and 6.6-7.91 GHz in the X direction,and band bands of 4.23-6.69 GHz in the Y direction.Finally,the influence of dimensional changes on the band gap is discussed.(2)A uniplanar EBG structure was designed using the chemical structural formula of the compound Porphine(C20H14N4),and its electromagnetic band gap was measured using the suspended micro strip line method(suspended micro strip method).The results showed that the The bandwidth of the structure below-40dB is 100.38%.And improved the suspended microstrip line method,designed a 800MHz low-pass filter(LPF),passed the test,the porphine filter in-band(0-800MHz)S21>-1dB,the Out-of-band S21<-25dB,S11<-1dB when frequency bigger than 4.4GHz,.(3)The Multi-Via Mushroom-Type EBG(MVM-EBG)structure is combined with a coplanar waveguide micro strip antenna.The antenna size is 32.3mm×35mm×1.6mm,and the EBG size is 12mm×12mm.The two-,three-,and four-Via EBG structures were connected to the coplanar waveguide antenna feeder end,respectively,and the effects of different positions of the through holes on the filtering performance of the EBG structure filter were investigated.The results show that different return hole positions will generate different return losses.By adjusting the position of the through holes,antennas with operating frequencies of 5.02-5.44 GHz,7.10-7.37 GHz,and 9.34-9.69 GHz were generated.The above research results provide ideas for designing chemical molecular structural EBG structures,and provide ideas for the combination of chemical molecular structural EBGs with filters and antennas.