A Compact Wideband Circularly Polarized Planar Monopole Antenna for Wireless and X-Band Applications

This paper presents a compact and wideband circularly polarized planar monopole antenna designed for wireless applications and X-Band frequency range, covering 4.1 GHz, 5.8 GHz, 6.5 GHz, and 10 GHz. The proposed antenna utilizes an L-shaped feedline, two slotted patches, a concentric ring, and a modified partial ground plane. The ground plane is enhanced with two extended rectangular protrusions to achieve wideband Circular Polarization (CP) within a compact form factor. The prototype’s overall dimensions are remarkably compact at 0.342$\lambda_{0}\times$ 0.438$\lambda_{0}\times$ 0.022$\lambda_{0}$ ($\lambda_{0}$ at 4.1 GHz). Simulated results indicate an impedance bandwidth of 9.16% (3.96-4.34 GHz) and an impressive 73.34% (5.50-11.87 GHz). Additionally, a 3-dB axial ratio bandwidth of 6.10% (3.97-4.22 GHz), 5.98% (6.16-6.54 GHz), and 10.9% (7.07-7.84 GHz) is achieved. The antenna attains a peak gain of 6.7 dB within the operating frequency range. The proposed antenna demonstrates suitability for circular polarization applications in the X-Band and Wireless Local Area Network (WLAN) applications, offering a compact yet high-performance solution.