A compact triple band circularly polarized planar antenna for wireless application

Abstract

AbstractA compact planar triple band circularly polarized (CP) antenna loaded with parasitic elements is proposed for wireless applications. For achieving circular polarization 2 inverted L‐shaped strips are added to the longer arm of dual band monopole and ground plane. A rectangular patch and a U shaped radiator are added to increase the impedance bandwidth as well as polarization purity. Electrical size of the antenna is 0.32λ × 0.32λ, where λ is the free space wavelength at its lowest CP frequency that is, 2.4 GHz. The structure shows an impedance bandwidths (│S11│ ≤ –10 dB) of 870 MHz (1.83‐2.7 GHz), 1.17 GHz (3.27‐4.44 GHz), and 400 MHz (4.75‐5.15 GHz). The 3‐dB axial ratio bandwidths of the proposed structure are 12.2%, 5.3%, and 4.28% at 2.375, 3.47, and 4.9 GHz of center frequencies respectively. The proposed structure is fabricated and its parameters are measured. Measured results nearly match with the simulated results and it shows satisfactory gain in all the three operating CP bands.