LAUSR

ABSTRACT A single fed monopole antenna for circularly polarised quad-band applications is presented. The antenna radiator is comprised of half ring-shaped arcs integrated with the 50Ω microstrip feed line. In the proposed design, the circular polarisation is achieved by means of integrating ring, stubs and implanting an open-ended C-shaped slot in the ground surface. The designed antenna has a −10 dB impedance bandwidth in the range of 2.41 GHz to 4.14 GHz and 4.34 GHz to 6.33 GHz. The 3-dB axial ratio bandwidth varies from 3.01 to 3.21 GHz, 3.46 to 3.79 GHz, 4.53 to 4.68 GHz and 5.08 to 5.10 GHz, therefore, exciting four circularly polarised bands. The proposed antenna covers almost all the IEEE 802.11 and IEEE 802.16 standards and may be a suitable candidate for WLAN and WiMAX applications. The optimisation of the designed antenna is conducted using tool Ansys HFSS and found simulated results in a good match with measured results.