Wideband DRA Array Placed on Array of Slot Windows

A dielectric resonator antenna (DRA) with ε_r = 35.9 and excited by a printed microstrip line is considered. Such an element achieves 4% matching bandwidth with unidirectional radiation patterns. However, when a rectangular slot is fabricated on the ground plane under the DRA, a 60% bandwidth is achieved with bidirectional radiation patterns. The mutual coupling between two elements is found to be of low level for the entire bandwidth. To improve the front-to-back ratio of the antenna, a reflector made of conducting strips parallel to the antenna polarization is placed behind the slot window. Linear (H- and E-planes) and planar arrays are fabricated and tested achieving good agreement between simulated and measured results providing high confidence on the simulation.