Bandwidth enhancement of helix excited cylindrical dielectric resonator antennas by means of stacking

Stacking method is used to enhance the 3 dB axial ratio and impedance bandwidth of the circularly polarized cylindrical dielectric resonator antennas excited by an external tape helix. In this method, a dielectric cylinder with lower permittivity than the basement cylindrical dielectric resonator is placed concentrically on top of the basement cylinder. The new configuration offers an axial ratio bandwidth up to 11% and impedance bandwidth of 31%.