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 \(^\circ\) ${}^{\circ }$ 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 \(^\circ\) ${}^{\circ }$ to ± 60 \(^\circ\) ${}^{\circ }$ .