Back Lobe Suppression of a Microstrip Patch Antenna by Partial Removal of Ground Plane

This paper presents a novel method to improve the Front-To-Back Ratio (FTBR) of an inset-fed microstrip patch antenna. By etching slots in the ground plane, the back radiation of such an antenna gets suppressed. Slots were made symmetrically on the four edges of the rectangular ground plane. The method is applicable for any frequency easily in the lower GHz range. The back radiation which has been suppressed reaches a value of -34.17 dBi, which is much below the level of a standared microstrip antenna having a value -10.6 dBi. Horizontal Half Power Beam width (HPBW) has increased from 94° to 119.3°, Reflection co-efficient from -12.83 to -43.5 and the Voltage Standing Wave Ratio (VSWR) decreased from 1.59 to 1.01. The particular aspect of this design is in etching horizontal and vertical slots in the ground plane at optimally located distances.