Design guidelines for multi-layer dielectric rod antennas fed by Vivaldi antennas

Dielectric rod antennas of circular cross-sections have been numerically investigated. Various structures of finite-length rods are compared as functions of their different physical parameters, such as the rods´ diameter, length, dielectric constant, multi-layer and finally the effect of corrugation. The far-field radiation pattern characteristics of these various antennas are presented as well. Results indicate that the operating bandwidth of these antennas can be extended by utilising either a core with a high dielectric constant and a cladding layer with a lower dielectric constant or equivalently a corrugated rod of the high dielectric constant material. The simulation of the various types of rod antennas have been compared with the measurement and very good agreement has been achieved.