Dielectric Resonator Antennas
Dielectric resonator antennas (DRAs) consist of a block of substrate or combinations of substrates of different shapes. DRAs are characterized by small size, high radiation efficiency, and large impedance bandwidth. Due to absence of conducting materials, DRAs have low conductor losses and surface wave losses. DRAs are suitable in millimeter wave applications like radio astronomy, remote sensing, WirelessHD technology, radar systems, and cancer imaging.
DRAs are widely used compared to microstrip antennas due to their design flexibility and compactness. Rectangular DRAs are used for moderate gain over large ground planes with good efficiency. Cylindrical DRAs are commonly used with circular polarized cases and to get better gains with symmetrical patterns.