Accurate Characterization of Electromagnetic Band-Gap Structures

Yosef T Aladadi,Majeed A S Alkanhal

doi:10.1109/access.2021.3109085

Yosef T Aladadi, Majeed A S Alkanhal

Open Access

https://doi.org/10.1109/access.2021.3109085

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Abstract

In this paper, electromagnetic band-gap (EBG) structures are accurately characterized using a free-space method. The field transmission and reflection parameters are exploited to determine the effective material parameters both inside and outside the band-gap regions of the EBG structures. The electromagnetic (EM) properties of the effective refractive index, effective wave impedance, effective permittivity, and effective permeability at multiple band-gap regions are derived from a single scattering computation. The derived phase and attenuation constants correctly define the boundaries of the band-gap region and the level of attenuation within the band gap. Deviations in the incidence angle from the normal direction alter the EM properties; hence, the operating bandwidth of the band-gap region is as expected due to the inherent structure anisotropy of the unit cells.

Highlights

Artificial electromagnetic band-gap (EBG) structures are typically created using two- or three-dimensional periodic metallic and dielectric structures [1]–[3]
Surface waves occur on the interfaces between two dissimilar materials such as metal and free space; these waves are bound to the interface and decay exponentially into the surrounding materials
EBG periodic structures have high EM surface impedance that is capable of suppressing the propagation of surface waves and acting as an in-phase reflector within a certain frequency range [6], [9]–[12]

Summary

INTRODUCTION

Artificial electromagnetic band-gap (EBG) structures are typically created using two- or three-dimensional periodic metallic and dielectric structures [1]–[3]. Metallic parallelplate waveguides (PPWGs) [1], [5] and glide-symmetric unit cells [6]–[8] are considered of the illustrious EBG periodic structures They show a frequency band gap through which surface waves cannot propagate. The proposed method provides full information about the effective EM properties of the EBG structures (neff , Zeff , εeff , μeff ) both inside and outside the band-gap region. These extracted parameters are utilized to determine the frequency boundaries of the band gap and the properties of band gaps such as the effective phase and attenuation constants at wide bands and different incident angles. This behavior in all cells with the angle of incidence is attributable to the level of anisotropy in the different EBG cell structures

COMPARISONS OF CHARACTERIZATION METHODS

CONCLUSION