Bandwidth enhancement of probe-fed dielectric ring resonator antenna with parasitic element

Dielectric resonators (DR) find application in the design of microwave antennas. The radiation patterns of DR antennas are related to their excited resonant model(s). Dielectric resonators of low dielectric constant are usually employed to give a reasonable impedance bandwidth. We demonstrate that the bandwidth of a center probe-fed cylindrical dielectric ring resonator antenna can be increased by stacking another DR of the same dimensions on the top of the fed DR. The return loss and the radiation patterns of the stacked DR antenna are computed using the finite difference time-domain (FD-TD) method. The numerical results so obtained are compared to experimental measurements.<>