A Compact High-Gain Circularly Polarized Wideband Antenna Array with Sequential Phase Feed and Truncated Ground for ISM, 5G Mid-Band and Ku-Band Applications

This paper introduces a novel approach for enhancing gain in a wideband circularly polarized 2 × 2 antenna array by employing a sequential rotation technique. A meandered square patch with truncated corners is used as a single element in a 4-element array. The measured reflection coefficient |S11|< −10 dB covers a wideband from 1.8 to 18 GHz with a resonance of −28.49 dB at 2.4 GHz. 3 dB axial ratio (AR) bandwidth of 45.16% (2.4–3.8 GHz) and a maximum gain of 22.67 dB at 3.8 GHz is obtained. The antenna covers the ISM Band for biomedical applications, the mid-band 5G spectrum suitable for high-speed communications, and the Ku band for satellite applications. The overall dimension of the antenna is 66 ×\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times $$\end{document} 66 ×\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times $$\end{document} 1.6 mm3 (0.528λ0×0.528λ0×0.0128λ0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$0.528{\lambda }_{0} \times {0.528\lambda }_{0}\times 0.0128{\lambda }_{0}$$\end{document}) where λ0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\lambda }_{0}$$\end{document} corresponds to the resonant frequency at 2.4 GHz. The effectiveness of the proposed design is demonstrated by its high gain and axial ratio bandwidth below 3 dB. Measured results in free space as well as on-body are in good agreement with the simulated results. The truncated ground with four curved slots is used to obtain improved impedance matching and circular polarization.