Date Added: Aug 2012
A resonant antenna was proposed by Professor S. A. Long in 1983. The Dielectric Resonator Antennas (DRAs) offer several advantages, such as small size, low dissipation loss. Since the DRA has negligible metallic loss, it is highly efficient when operated at millimeter wave frequencies. The shapes of DRAs are various-simple ones, such as a hemispherical DRA, a cylindrical DRA and a rectangular DRA, and improved ones, such as truncated tetrahedron shape, split cone shape and half-hemispherical shape DRAs. DRAs can be excited with different feeding mechanism, such as coaxial feed, aperture, microstrip line and co-planar lines.