Additively Manufactured Multi-Material Dual-Band Millimeter-Wave Reflectarray for Beyond 5G

Abstract

This article presents a millimeter-wave (mm-wave) K-band and D-band large-frequency-ratio reflectarray for Internet of Things (IoT) devices, fabricated using industrial-level multi-material additive manufacturing. The reflectarray’s unit cell (UC) employs a metallic resonant patch embedded in the printed dielectric material. By adjusting the vertical position of the patch, different electromagnetic wave reflection paths are obtained. This provides an additional degree of freedom for phase shifting. Specifically, phase shifting in the K-band relies entirely on the different lengths of reflection paths. In contrast, the D-band phase-shifting depends on metallic resonant patches with varied sizes and the different lengths of reflection paths. This unique configuration effectively avoids the coupling issues that challenge conventional dual-band reflectarrays. Besides, the period of the UC can be sufficiently small at K-band (only 0.1 free-space wavelengths) to provide good phase correction and a large beam tilting angle. The reflectarray with multiple metal layers is implemented in a single substrate with an ultrathin profile, using the advanced multi-material industrial-level additive manufacturing technique. The reflectarray antenna can be potentially used in base stations for K-band satellite communications (SatComs) and mm-wave point-to-point beyond 5G communications simultaneously.