A 21.6-45 GHz Low-Profile Wideband Slot Antenna Array for 5G Wireless

Abstract

In this paper, a low-profile 21.6-45 GHz printed $1\times 4$ antenna array with high gain and efficiency is presented. Such antenna array is composed of an in-phase 1:4 power divider and four slot antenna elements. Each antenna element fed by the $50\ \Omega$ microstrip input/output (I/O) port consists of a C-shaped slotline and two ring slots with embedded defected ground structure (DGS). Multiple resonances are introduced by the proposed structure to achieve a wide operation bandwidth. To verify the mechanism mentioned above, a wideband slot antenna array is implemented and fabricated with a compact size of $28\times 40\times 0.254\ \text{mm}^{3}$. The measured result exhibits a 70.3% impedance bandwidth operating from 21.6 to 45 GHz. With such high performance, the proposed wideband antenna array can be a good candidate for 5G communication systems.