A back lobe reduction of aperture coupled microstrip antenna using DGS

This paper presents a novel design of aperture coupled microstrip antenna with back lobe reduction. The proposed design was based on the structure of a 2 by 2 planar array antenna with separated feeding technique, aperture coupler. The antenna is designed on Rogers Duroid substrate having dielectric, ε, of 2.2. Four dumbbell shaped DGS were etched on the ground plane for back radiation reduction. An antenna without DGS is first designed acting as reference. Both of the designs were simulated in CST Microwave Studio 2011 software based on operating frequency of 5.8GHz. A parametric study was done to investigate the effect of DGS dimensions. The results show that, by incorporating DGS onto the antenna, back radiation is reduced. The back lobe level is reduced from 4.6dB to 0.4887dB. Return loss were also improved from -26.089dB to -41.28dB. This design concept can be useful in reducing the back radiation of aperture coupled microstrip antenna.