Dielectric Resonator Antenna
Encyclopedia
If the dielectric resonator
is placed in an open environment, power is lost in the radiated fields. This fact makes dielectric resonators useful as antenna elements.
Dielectric resonator antennas (DRA) offer following attractive features:
Dielectric resonator
A dielectric resonator is an electronic component that exhibits resonance for a narrow range of frequencies, generally in the microwave band. The resonance is similar to that of a circular hollow metallic waveguide, except that the boundary is defined by large change in permittivity rather than by...
is placed in an open environment, power is lost in the radiated fields. This fact makes dielectric resonators useful as antenna elements.
Dielectric resonator antennas (DRA) offer following attractive features:
- The dimension of a DRA is of the order of
, where 
; is the free-space wavelength and 
is the dielectric constant of the resonator material. Thus, by choosing a high value of 
(
), the size of the DRA can be significantly reduced. - There is no inherent conductor loss in dielectric resonators. This leads to high radiation efficiency of the antenna. This feature is especially attractive for millimeter (mm)-wave antennas, where the loss in metal fabricated antennas can be high.
- DRAs offer simple coupling schemes to nearly all transmission lines used at microwave and mm-wave frequencies. This makes them suitable for integration into different planar technologies. The coupling between a DRA and the planar transmission line can be easily controlled by varying the position of the DRA with respect to the line. The performance of DRA can therefore be easily optimized experimentally.
- The operating bandwidth of a DRA can be varied over a wide range by suitably choosing resonator parameters. For example, the bandwidth of the lower order modes of a DRA can be easily varied from a fraction of a percent to about 10% or more by the suitable choice of the dielectric constant of the resonator material.
- Each mode of a DRA has a unique internal and associated external field distribution. Therefore, different radiation characteristics can be obtained by exciting different modes of a DRA.