Dual-Band and Dual-Polarized Shared-Aperture Phased-Array Antennas With Enhanced Beam Coverage for 5G FR2 and 6G FR3

This article proposes an antenna that employs the shared aperture concept and is devised to simultaneously operate in the dual bands of Ku and Ka while supporting dual polarization. The antenna element is specified according to the four distinct derivation processes. The port isolation is enhanced by using an indirect feeding mechanism through slot aperture coupling integrated with substrate integrated waveguide (SIW) feed. Based on the antenna array theory, the extended array structure ensures optimized interantenna spacings. The reflection coefficient of the antenna element satisfies below −10 dB for both operating bands. In addition, interport isolation surpasses 30 dB in Ku-band and 20 dB in Ka-band. For the demonstration of beam-steering capabilities, distinct array structures are devised and constructed for each band. Both simulations and measurements for the Ku-band feature a beam-steering angle exceeding ±40° for both polarizations, with a peak gain of 10.3 dBi based on a $1\times3$ array antenna structure. In the case of the Ka-band, measurements and simulations consistently demonstrate a beam-steering angle of no less than ±43° across both polarizations. This results in a maximum gain of 13.1 dBi based on a $1\times5$ array antenna structure.

I. Introduction

With the advancement and proliferation of the millimeter-wave spectrum, deploying extensive frequency resources to deliver high-speed and low-latency services to users is progressively becoming achievable [1], [2], [3]. Furthermore, advanced 5G and anticipated 6G wireless communications, expected for commercialization by 2030, are emerging as key technologies to realize new applications, including mixed reality, metaverse, radar, sensing, imaging, and satellite communications [4], [5], [6]. The sub-THz frequency range, notably above 100 GHz and being discussed as a potential standard for 6G, promises unprecedented data rates reaching into the terabits per second due to the availability of ultra-wideband frequency assets. This potential has sparked numerous research activities aimed at exploiting its significant benefits [7], [8], [9]. In addition, the so-called upper-mid band or 6G frequency range 3 (FR3: 7–24 GHz) spectrum, which remains unlicensed, is attracting significant attention [10], [11], [12]. When compared to the 5G FR2 band, it has advantages in terms of path loss and coverage. Meanwhile, compared with 5G FR1, it facilitates the use of a more expansive channel bandwidth.