Efficiency enhancement of a circularly polarised slotted waveguide antenna array for Sub-THz applications

This manuscript presents a simple and compact, high gain & highly efficient wideband circularly polarised slotted waveguide antenna array based on WR-3 waveguide. The proposed geometry is based on a cross-slot-based element capable of providing a wide circular polarisation bandwidth. These slots are connected to each other through horizontal slots. Hexagonal slots of finite circumradii are cut at the center of the cross slots along with a series feed across the WR-3 waveguide, which results in a gain of up to 14.4 dBi and a fractional bandwidth of 27.2%. Furthermore, a grooved metal cabin flared at 45∘\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^\circ$$\end{document} is used as an enclosure, which enhances the gain. The grooved metal cabin provides a state-of-the-art gain, efficiency, and fractional bandwidth of 17.8dBi, 98.6%, and 34.5%, respectively. It also facilitates beam scanning over a span from ±34∘\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^\circ$$\end{document} to ± 60∘\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^\circ$$\end{document}.