Multibeam Antenna With Low-Beam Squint for mm-Wave 5G Handset Applications

In this letter, a novel series-fed periodic microstrip antenna array with reduced beam squint is proposed for the 28 GHz millimeter (mm)-wave 5G band. To mitigate beam squint, the design reduces the dispersion in the unit cell by introducing an L-shaped slot pair on an elliptical microstrip patch. Further improvements are achieved by utilizing the corresponding tapering and matching sections. The proposed array has a low-beam squint angle of only 2° over a 3 GHz bandwidth, which is a decade lower than the conventional series-fed microstrip rectangular patch array. The gain fluctuation is limited to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm 1.5$</tex-math></inline-formula> dB between 26.5 GHz and 29.5 GHz. Moreover, the final antenna achieves an angular coverage from −37° to 40°. With its beam squint assessment capability, the proposed multibeam solution is a promising candidate for mm-wave 5G cellular applications.