Circularly Polarized Wideband-to-Narrowband Switchable Antenna

Abstract

This paper presents a circularly polarized printed wideband-to-narrowband switchable monopole antenna for UWB/WiMAX applications. The proposed switching antenna consists of circularly polarized monopole antenna for the UWB mode with two bandpass filters integrated into the feeding network for the two 3.5/5.5 GHz center frequencies narrowband modes. The proposed antenna is utilized to operate at triple modes; 7.3 GHz, 3.5 GHz, and 5.5 GHz with wide impedance bandwidth (117.6%, 16.7%, and 7.3%), wide axial ratio bandwidth (89.2%, 16.7%, and 7.3 %), and the gain reaches (6.91 dBi, 5.5 dBi, and 4.2 dBi).