A dielectric resonator antenna (DRA) is a radio antenna mostly used at microwave frequencies and higher, that consists of a block of ceramic material of various shapes, the dielectric resonator, mounted on a metal surface, a ground plane.
[1] An advantage of dielectric resonator antennas is they lack metal parts, which become lossy at high frequencies, dissipating energy.
[1] Dielectric waveguide antennas are used in some compact portable wireless devices, and military millimeter-wave radar equipment.
[3] In that very first investigation, Long et al. explored HEM11d mode in a cylindrical shaped ceramic block to radiate broadside.
[4] An antenna like effect is achieved by periodic swing of electrons from its capacitive element to the ground plane which behaves like an inductor.