Analysis and design of a dual-band circularly polarized microstrip patch antenna

In the last decade a great effort has been made concerning research on frequency agility of microstrip patch antennas. In all these attempts an increase in length or height of the patch is generally expected and there is a tradeoff between wider bandwidth and good axial ratio. This paper presents the analysis and design of a novel dual-band circularly polarized microstrip patch antenna using a spur-line band-stop filter and a perturbation segment technique. This dual frequency operation can be obtained without increasing either the size or the thickness of the patch while other features are not degraded