Backward Radiation Reduction and Bandwidth Enhancement of Metamaterial Antenna for UWB Applications

A metamaterial inspired planar-patterned microstrip patch antenna, feeding on a Duroid substrate inset bottom ground soft-surface, is presented for ultra-wide band (UWB) applications. The present antenna is configured on a step-edge periodic unit-cell pattern, with a tiny air gap etched on the metal patch and finite ground plane. By employing these structures an ultra-wide band from 4 GHz ~ 16.2 GHz is achieved. The important advantage is retaining the suppression of back radiation while removing grounded edge metallic parts and replacing them with the finite cut-off square unit cell. The feeding ground plane and radiating patch are specially configured to develop artificial structures using series capacitance and shunt inductance. The efficiency of the proposed antenna is above 99.1%. To enhance gain and bandwidth, this antenna has etched Jerusalem crossed slots on the ground plane and star-slots on the patch, with the enhanced gain reaching a maximum of 8 dBi at 9.2 GHz. The antenna's overall dimensions exhibit 0.72λ × 0.83λ × 0.05λ at a 10.1 GHz cut-off frequency. The high absorption gain, directivity, and enhanced frequency bandwidth, verified by numerical modeling and experimentation, ensure the proposed antenna is well suited to any UWB application.