Harmonic suppression of monopole wideband antenna with DGS for operating frequency at 3.5GHz

This paper presents the integration of a microstrip monopole antenna and defected ground structure (DGS) for harmonic suppression. The main contribution of this structure is the utilization of the widely available substrate with a simple design to improve the power quality by harmonics suppression. Since the microstrip monopole antenna already offers wideband characteristics, the DGS is incorporated in the design to achieve a stop band in the undesired frequencies while widening the rejection band. The main objective of this paper is to achieve a focused frequency bandwidth centered at 3.5 GHz frequency with no harmonics for high quality antenna for future 5G application. To achieve this, a modified rectangular patch is designed to obtain wideband frequency at 3.5 GHz. Next, a DGS structure is placed at the ground plane of the antenna to ensure the undesired frequencies are suppressed for better power quality and wideband operating frequency at 3.5 GHz. Next, a DGS structure is placed at the ground plane of the antenna to ensure the undesired frequencies are suppressed for better power quality. The proposed work is designed and simulated using CST Studio Suite 2022. The results show that by implementing the DGS on the ground plane of the proposed antenna, the frequencies ranging from 4.3 GHz up to 8 GHz are successfully suppressed. Plus, even with the addition of the DGS structure at the ground plane of the antenna, the efficiency of the antenna remains high at 91.02% and there is negligible change in the radiation pattern. However, the gain of the antenna decreased by 1.53 dB.