Design of broadband circularly polarized THz antenna with stable radiation pattern for 6G communications

Abstract

This paper presents a compact efficient and stable high gain broadside circularly polarized (CP) antenna using WR3 waveguide. Asymmetrical H-shaped slot arrays deployed on the broadside wall of the waveguide, suits the antenna for operating in the Sub THz range of frequencies. The designed antenna operates almost entire frequency range of WR3 waveguide from 227 GHz to 380 GHz with a return loss ≤ −10 dB roofing the WM834 band. The proposed antenna possesses a wide axial ratio bandwidth (ARBW) of 28.28 GHz spanning from 289.1 GHz to 317.38 GHz with persistent gain and exhibits a minimum axial ratio of 0.72 dB in the range of 296–309 GHz. Furthermore, the model attains a maximum directivity of 16.5 dBi and a peak gain of 16.1 dBi at 317 GHz with the first sidelobe level (SLL) of − 13.6 dB and radiation efficiency of 97.5% towards the broadside direction. Apart from the stable pattern in the CP band, beam scanning of the main lobe from 250 GHz to 340 GHz is also observed. The proposed antenna has been designed, simulated, and optimized using CST microwave studio and the results are validated using HFSS software.