Meandered Inductor Shape of DGS for Coupling Suppression Between Adjacent Elements of Array Antenna

Abstract

Defected ground structure (DGS) has been recently applied to enhance the bandwidth and gain of microstrip antenna, as well as to effectively improve the radiation characteristics by suppressing the higher mode harmonics and coupling between adjacent elements of array antenna. This paper presents the use of DGS which takes meandered inductor (MI) shape to improve the return loss ($S_{11}$) and to suppress the coupling between adjacent elements ($S_{21}$) of array antenna. An FR4 epoxy dielectric substrate with the thickness of 1.6 mm is used for deploying the antenna. The MI shape slot is embedded on the groundplane at the bottom side of dielectric substrate between two elements of array antenna which are deployed on the top side. The simulated results show that values of $S_{11}$ and $S_{21}$ have been improved up to 4.4 dB and 1.9 dB, respectively, at the resonant frequency of 2 GHz. This is comparable with the measured results which have achievement up to 8 dB and 5 dB for $S_{11}$ and $S_{21}$, respectively.