In 1983, M.W. McAllister showed that dielectric slab placed on a ground plane and excited by a pin or probe fed through the ground plane into the dielectric will radiate at its resonant frequency.
This characteristic was employed to introduce a new antenna family: Dielectric resonator antennas. (DRAs). DRAs mostly use dielectric materials with high dielectric constants resulting in structures that are small compared to a free-space wavelength and can handle high power over wide temperature ranges.
DRAs may be realized using various resonator shapes (which may be made up of regions with different dielectric properties) and may be excited in various ways (including coupling through an aperture in the ground plane or from a probe located near the dielectric). ...
This Cubic DRA antenna is the first of its class to be included in Antenna Magus and consists of a uniform dielectric cube fed using a short coaxial probe that is embedded in the dielectric. The antenna radiates a linearly polarized, medium gain, single broadside lobe with a peak gain normal to the ground plane. A relatively wide impedance bandwidth can be achieved when compared to other narrowband structures like typical microstrip patch antennas.