Gain Enhancement in Microstrip-Feed Patch Antenna Using Metallic Ring and DGS

A microstrip patch antenna is designed that have metallic ring coplanar to radiation patch and defected ground structure to enhance the gain is proposed. The design forces conversion of the surface wave energy into the space wave energy by the scattering of surface waves from metallic ring. The metallic ring is placed around the metal patch at a distance of d1 from the edges of the metal patch and width of metallic ring is d2. Initial values of d1 and d2 are one-quarter of free pace wavelength (d1=d2=4λ0/16). Using CST Microwave studio, the results of the patch antenna without metallic ring and solid ground plane, second patch surrounded by metallic ring and DGS are simulated and compared. The proposed microstrip patch antenna operates at the 5.8 GHz frequency suitable for WLAN applications. By this proposed antenna design there is enhancement in the gain of microstrip patch antenna about 4.3 dB as compared to conventional one (without metallic ring and solid ground plane) without reducing impedance bandwidth.