Summary
International Symposium on Antennas and Propagation
2009
Session Number:2A1
Session:
Number:2A1-1
From a PEC Ground Plane to an EBG Surface:Understanding the Underlying Physics
Yahya Rahmat-Samii, Harish Rajagopalan,
pp.285-288
Publication Date:2009/10/21
Online ISSN:2188-5079
Summary:
Low profile antenna designs form extremely attractive solutions for wireless communications and mobile devices. [1] provides ample references for the existing state-of-the-art electromagnetic band-gap (EBG) structures. The challenge in these designs is to decouple the effect of the adjacent ground plane from the antenna itself. For example, when an electric dipole antenna is placed closely parallel to perfect electric conductor (PEC) ground plane due to the reverse image current (image theory), the antenna performance is severely compromised. In order to overcome this ground plane and antenna interaction, artificial complex ground planes such as electromagnetic band-gap (EBG) structures have been proposed. Due to their unique electromagnetic properties like in-phase reflection and surface wave suppression, EBG structures have garnered considerable research interest in the antenna design community. The focus of this work is to systematically evolve from PEC to EBG and try to understand the underlying physical mechanisms involved in the whole process. In order to analyze the features of EBG (mushroom-like) structures we utilize full wave electromagnetic simulators based on advanced numerical methods. These EBG (periodic) structures consist of patches connected to the PEC ground plane through vias. The EBG structures are characterized based on their reflection phase, dispersion diagrams and band-gaps. Some of the applications of these EBG surfaces include antenna substrate for surface wave mitigation and reflection/transmission surfaces for high gain antennas. Firstly, the reflection phase characterization of the PEC ground plane, via loaded PEC ground plane, patch loaded PEC ground plane and EBG surface is performed in that order. Next, the dispersion diagram characterization for patch loaded PEC ground plane and EBG surface is discussed to identify the stop band. Finally, an electric dipole is selected as a test antenna and placed close to PEC ground plane, patch loaded PEC ground plane and EBG surface and the antenna performance is evaluated.