Broadband dual-sense enhanced axial ratio bandwidth circular polarized monopole antenna for WLAN/WiMAX/X/Ku/K-bands applications

In this work, broadband circularly polarized monopole antenna is proposed. The proposed antenna is designed by an FR4 substrate with a dielectric constant of 4.4 and thickness $$h = 1.6\;{\text{mm}}$$ . The size of the designed antenna is $$0.99\lambda_{0} \times 0.99\lambda_{0} \times 0.07\lambda_{0}$$ , where $$\lambda_{0}$$ is the free space wavelength at the center frequency of $$f_{0} = 12.36\;{\text{GHz}}$$ . A stub and a parasitic strip are loaded at the optimum positions on the ground plane to improve the results. The stub and parasitic strip helps to develop two orthogonal modes with the same amplitude for circular polarization. The proposed antenna offers − 10 dB simulated impedance bandwidth of 126% (4.55–20.16 GHz) and measured more than 129% (4.4–20.5 GHz). The 3-dB axial-ratio bandwidth (ARBW) of the monopole antenna is significantly enhanced by using a modified planar ground structure under the proposed patch. There are two 3-dB simulated and measured axial-ratio bandwidth (ARBW) of 86.5% (5.51–13.91 GHz), 16.7% (17.77–21 GHz) and 86.54% (5.5–13.89 GHz), more than 16.71% (17.76–21 GHz) achieved. The fabricated antenna is strongly desirable for WLAN (5.2–5.8 GHz), WiMAX (5.7–5.85 GHz), X-band (8–12 GHz), Ku-band (12–18 GHz) and fractional part of the K-band applications of wireless communication.