Design of a compact CP antenna with enhanced bandwidth using a novel hexagonal ring based reactive impedance substrate

Abstract

A novel hexagonal ring-based reactive impedance surface (RIS) has been proposed and comprehensively employed as a ground plane of a circular polarized patch antenna (CPPA) for enhancing impedance bandwidth (IBW) and axial ratio bandwidth (ARBW), simultaneously. Furthermore, a simple analytical model analysis has been developed to estimate the resonance frequency and to predict the surface characteristics of the RIS structure. Two slits over the patch render the antenna to radiate circular polarized (CP) wave. The RIS has improved the CP antenna performance in terms of compactness, improved gain and increased efficiency. The proposed loaded structure has been numerically and experimentally studied with a layout of 40 × 40 × 3.2 mm3 at 3.7 GHz. The measured results indicate that the prototype antenna has produced a relatively wider IBW and ARBW of 9.32% and 2.1%, respectively with peak gain about 2.98 dBiC. Both gain and efficiency of the loaded structure have been improved owing to the low conductive loss of the ring-shaped RIS. The proposed CP antenna might be suitable for radar application used in S-band.