In this study, a high-gain wideband circularly polarized (CP) printed monopole antenna for wireless local-area network (WLAN), worldwide interoperability for microwave access or WiMAX, C-band, and multiple input, multiple output (MIMO) applications was proposed and demonstrated. The proposed antenna structure has an octal-shaped monopole antenna tilted by 20° from its longitudinal axis, excited by coaxial probe feeding, and partial ground plane. To
achieve broadband CP performance, the ground plane was redesigned with etching slots. A 1.6-mm-deep FR-4 (Ԑr = 4.3) substrate with dimensions of 70x55 mm2 is used to create and test a prototype of the suggested antenna. The proposed antenna's measurement results satisfy requirements for a broad ARBW
of 107% (1.83-6.05 GHz), a broad impedance bandwidth of 139.39% (2-11.2 GHz), and a maximum gain of 7.28 dBi.