3‐D printed circularly polarized multibeam antenna array with full azimuth scanning capability and wideband characteristic for 5G millimeter‐wave applications

Abstract

This paper presents a wideband circularly polarized (CP) multibeam antenna array, which is with full azimuth scanning capability and operates in Ka band for 5G applications. It adopts a circular array configuration and consists of 18 elements with a simple structure. Regarding to each element, it is fed by a 90 bent rectangular waveguide and employs a simplified single dielectric slab polarizer to produce CP waves. Within the axial ratio bandwidth (ARBW), the proposed element can achieve a stable half power beamwidth (HPBW) of 29 ± 7 , while, the 3-dB AR beamwidth is larger than the HPBW. By switching the active elements, the proposed array can realize 360 beam steering in azimuth plane, while, the HPBW and the 3-dB AR beamwidth cover the entire plane. To simplify the fabrication process, dielectric and metal 3-D printing technologies are employed for processing. Experimental results indicate that the proposed array can achieve a 40.5% 3-dB ARBW which almost covers the entire Ka band from 26.2 to 39.5 GHz and a gain of 9.9 ± 1.5 dBic. The front-to-back ratio (FBR) of each beam is higher than 19 dB. In contrast to conventional designs, the proposed antenna features wide band, simple structure, and ease of fabrication.