EBG identification by the Reflection Phase Method (RPM) design for application WiFi antenna
ABSTRACT In a first part of this article, we present the method based on the reflection phase diagram for the identification of the EBG (electromagnetic band gap) structures. The procedure consists to plot the diagram of phase of the wave reflected by EBG structure excited by an incident wave, in the simplest case, plane and normal upon the structure. The forbidden band corresponds to the frequency band where the phase of the reflected wave is equal to 0plusmn45deg, criterion of Sievenpiper, or to 90plusmn45deg, criterion of Rahmat-Samii. In the filtered frequency band, the structure behaves as a magnetic conductor : a High-impedance surface. The EBG structure studied and designed is a Mushroom-like (D. Sievenpiper et al., 1999). The performances of this structure are modelled using the HFSS code. In the second part, we illustrate the application aimed by the design of this structure.
- SourceAvailable from: ku.edu[show abstract] [hide abstract]
ABSTRACT: Mushroom-like electromagnetic band-gap (EBG) structures exhibit unique electromagnetic properties that have led to a wide range of electromagnetic device applications. This paper focuses on the reflection phase feature of EBG surfaces: when plane waves normally illuminate an EBG structure, the phase of the reflected field changes continuously from 180° to -180° versus frequency. One important application of this feature is that one can replace a conventional perfect electric conductor (PEC) ground plane with an EBG ground plane for a low profile wire antenna design. For this design, the operational frequency band of an EBG structure is defined as the frequency region within which a low profile wire antenna radiates efficiently, namely, having a good return loss and radiation patterns. The operational frequency band is the overlap of the input-match frequency band and the surface-wave frequency bandgap. It is revealed that the reflection phase curve can be used to identify the input-match frequency band inside of which a low profile wire antenna exhibits a good return loss. The surface-wave frequency bandgap of the EBG surface that helps improve radiation patterns is very close to its input-match frequency band, resulting in an effective operational frequency band. In contrast, a thin grounded slab cannot work efficiently as a ground plane for low profile wire antennas because its surface-wave frequency bandgap and input-match frequency band do not overlap. Parametric studies have been performed to obtain design guidelines for EBG ground planes. Two novel EBG ground planes with interesting electromagnetic features are also presented. The rectangular patch EBG ground plane has a polarization dependent reflection phase and the slotted patch EBG ground plane shows a compact size.IEEE Transactions on Antennas and Propagation 11/2003; · 2.33 Impact Factor