Wide Band Designs of Rectangular Microstrip Antenna Using Modified Ground Plane

Wide band microstrip antenna is realized when more than one resonating modes are present in a single patch. This has been more frequently realized by using resonant slots embedded inside the radiating element. In this paper, wide band designs of rectangular microstrip antennas using modified ground plane (defected ground plane) on substrate thickness of 0.07 lambda(0), are proposed. The defects in ground plane alter higher order TM02 resonant mode frequency in the patch which gives bandwidth of 110 MHz (7.2%). Broadband configuration with slot on patch as well as the ground plane is presented. The two slots optimizes spacing between patch's TM10 mode with respect to TM02 modes on patch and on ground plane, to yield increased bandwidth of 275 MHz (16.6%). The proposed designs yields broadside radiation pattern over bandwidth with antenna gain of more than 6 dBi. The work proposed here clearly brings out and explains an effects of modifications in patch and ground plane in terms of resonant modes that realizes wider bandwidth.