Elliptical multiple ring monopole antennas

The effects of the ellipticity ratio and the thickness of the rings on the multiple ring monopole antennas are presented. Several multiple ring monopole antennas with different ellipticity ratios and thickness of the rings are designed, fabricated and measured. The results show that the resonance bandwidths can be controlled by the ellipticity ratio and changing the thickness of the rings causes a frequency shift at the fourth band but it does not have a significant effect on the lower bands.