Investigation On Novel Artificial Periodic Structures And Its Application

To achieve the electromagnetic applications(noise/guided wave suppression and space wave suppression)for the modern electronic information systems,the properties of two artificial periodic structures including Electromagnetic Bandgaps(EBGs)and Frequency Selective Surfaces(FSSs)have been researched in detail in this dissertation.According to the category of EBG and FSS,six kinds of the article periodic structures have been proposed.They are C-EBG,coupled C-slotline EBG,SC-EBG,3-D printed 3-D cross EBG,FSS based on 2.5-dimensional closed loop,and 3-D printed coaxial FSS,respectively.The details are summarized as follows:(1)A novel planar C-EBG power/ground plane is proposed to suppress the power/ground noise in lower frequencies below 1GHz.Its stopband has been investigated by the equivalent circuit modeling and mode analysis.The impact on the stopband of rotational asymmetry has also been considered and its power/ground noise suppression performances in the frequency and time domain have been given.(2)A novel coupled C-slotline EBG is poposed to suppress wideband common-mode noise.The proposed common-mode noise suppression circuit has been analyzed by the even/odd mode equivalent circuit model.Two kinds of coupling types have also been investigated by the even mode equivalent circuit model.(3)A miniaturized SC-EBG is proposed by adding metal rod in the unit cell of the original C-EBG to suppress the power/ground noise.The introduced metal rod can increase the equivalent capacitance of the unit cell effectively,decreasing the lower bound cutoff frequency.Moreover,the resonant cavity of the high order modes become more compact and complex due to the introduction of the metal rod,increasing the upper bound cutoff frequency of the stopband of the proposed miniaturized SC-EBG(4)3-D printing technology is used to design a 3-D cross EBG for parallel plate mode suppression in microstrip circuit shielded structures.The designed 3-D cross increases the equivalent capacitance and equivalent inductance of the unit cell,enhancing the stopband bandwidth and reducing the unit cell electric size.(5)A miniaturized stopband FSS is proposed based on 2.5-D closed loop.The 2.5-D closed loop consists of two pairs of C-type split square rings which is orthogonal for polarization insensitivity on top/bottom layer and four metal vias located in the middle of the unit cell.The two pairs of split square rings are connected in series by the four vias,forming the so called "2.5-dimensional closed loop" with longer length in total.Consequently,the FSS unit cell electric size is greatly decreased with respect to the resonant frequency.An equivalent circuit model has been established to explain the physical mechanism.(6)Moreover,3-D printing technology is also used to design a 3-D FSS with square coaxial structure.The 3-D FSS provides two electromagnetic wave propagation paths,and has mutil-transmission zeros/poles.These properties can be used to obtain a sharp transition from in-band to out-of-band characteristic and improve the out-of-band rejection.