Circular patch antenna with dumbbell defected ground structure (DGS) for WiMAX application / Azamie Mohd Jamadir

This paper presented the design of dumbbell shape defected ground structure (DGS) which implemented on circular patch microstrip antenna. The radiation performance of the antenna is characteristized by varying the geometry and dimension of the DGS. Dumbbell shape DGS is placed at specific position which required in the ground plane. Then, this geometry structure will disturb the shield current distribution of ground plane. The geometry chosen for DGS was dumbbell shape. This structure permits smaller antenna element that is increased the value of gain and directivity of the antenna as well reduce the antenna size. This project presented the simulation and measurement result between conventional antenna and circular patch antenna with dumbbell Defected Ground Structure (DGS). Then, the performance between them was compared. The simulation result simulate by using CST Microwave Studio software while measurement result measured by Vector Network Analyzer (VNA). The simulation result have verified that the dumbbell shape DGS has improved the performance of conventional antenna. The return loss enhances about 56.8% for simulation and 50.52% for measured value. The gain and directivity improved by 0.05 dB and 0.09 dBi respectively