Millimeter Wave Dual-Band Antenna Array on a Thin Flexible Substrate for 5G Applications

In this paper, we present a novel low-profile, flexible dual-band $\mathbf{4}\times \mathbf{1}$ stacked patch antenna for millimeter wave mobile communication. The antenna element is fed using capacitive feed and also parasitic elements are added to the main patch antenna, which enhances bandwidth capabilities across 27.1-28.7 GHz and 37.4-38.7 GHz. The $\mathbf{4}\times \mathbf{1}$ array achieves gains of 11 dBi for the lower band and 11.85 dBi for the higher band. The antenna demonstrates 82% efficiency for the lower band and 66% for the upper band, offering a practical solution for millimeter wave mobile communication. The overall size of this dual-band antenna array is $\mathbf{22}\ \mathbf{mm} \times \mathbf{9}\ \mathbf{mm}$ . The antenna is fabricated, and comparison of simulation and measurement results are presented.