The complex mode formation in propagating microstrip of two-dimensional perforation

This paper presents the modal characterizations of two-dimensional periodical perforated microstrip on uniform ground. The numerical method based on multi-port ABCD matrix is used to extract the complex propagation constants of the multi-port periodic microstrip structures. The extracted result shows that right-handed modes which have positive sloping phase constant, and left-handed modes which have negative sloping phase constant, are excited by the perforated periodic structure. The complex modes in the form of +α±jβ and -α±jβ are observed in the stopband. The dispersion characteristics exhibit the different modal behaviors in different coupled regions.