Ultra-wideband modified rectangular microstrip antenna

A new ultra-wideband planar microstrip antenna obtained by combining rectangular and circular shaped planar monopole patches is proposed. The optimum feed-line position is obtained individually for rectangular and circular patches by studying their surface current distributions. The rectangular and circular geometries are then merged to obtain a modified configuration. A parametric study for varying distances between the centers of the circular and rectangular patches and also for the gap between the radiating patch and the ground plane is conducted. The proposed configuration yields an optimum bandwidth of more than 8 GHz and a gain of 1 to 3 dBi over the bandwidth.