A Design of Millimeter-Wave Dual-Polarized SIW Phased Array Antenna Using Characteristic Mode Analysis

Abstract

A millimeter-wave dual-polarized beam-scanning substrate integrated waveguide (SIW) phased array is proposed for the 5G communications. The principle of the proposed antenna radiating element is first analyzed with the characteristic mode analysis to obtain a wide operating bandwidth. Then, the horizontally and vertically polarized radiations are excited by a differentially fed SIW cavity and a linearly tapered microstrip line through the coupled slots, respectively. To further validate the proposed design, a 1 × 4 phased array is fabricated and tested. The experiment results show that the 11.0% overlapped dual-polarization bandwidth is from 25.8 to 28.8 GHz with the return loss larger than 10 dB, and the isolation between the dual-polarization is higher than 31.5 dB. The measured far-field patterns demonstrate that the beam-scanning ranges can cover <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$ \pm 44^\circ $</tex-math></inline-formula> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${{\bf and}}$</tex-math></inline-formula> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$ \pm 41^\circ \ $</tex-math></inline-formula> at 28 GHz for the horizontal and vertical polarization, respectively.