A Wideband Tri-Band Shared-Aperture Antenna Array for 5G and 6G Applications

TL;DR

This work tackles the challenge of sharing a single antenna aperture across the LB, MB, and HB bands for 5G/6G, where cross-band scattering and coupling distort radiation patterns and reduce isolation. A CMA-guided design employs a segmented spiral LB radiator with serial resonators and suppressors to achieve wideband scattering suppression and impedance matching, complemented by planar ME dipoles for the MB and HB to avoid common-mode resonances. The integrated tri-band array demonstrates wide LB/$3.05$-$4.68$ GHz, MB/$6.2$-$10.0$ GHz, HB/$10.0$-$15.6$ GHz operation with cross-band isolation $>20$ dB and RCS reduction from $4.7$ to $21.5$ GHz by 128.2%, validated by measurements that agree with simulations. Overall, the proposed shared-aperture approach provides a practical path toward robust 5G/6G performance with wideband suppression of scattering and coupling.

Abstract

This work presents a wideband tri-band shared-aperture antenna array covering the 5G mid-band and 6G centimetric band. The challenge of scattering and coupling suppression is holistically addressed across the wide bands. Guided by characteristic mode analysis (CMA), a segmented spiral radiator is developed to mitigate high-frequency scattering and coupling while maintaining low-frequency radiation performance. Compared with a conventional tube radiator, the proposed spiral achieves a reduced radar cross-section (RCS) over 4.7-21.5 GHz (128.2%). With the aid of serial resonators, the segmented-spiral dipole achieves impedance matching in the low band (LB, 3.05-4.68 GHz, 42.2%), covering the 5G band (3.3-4.2 GHz), while additional suppressors further reduce cross-band coupling. The middle band (MB) and high band (HB) antennas operate at 6.2-10.0 GHz (46.9%) and 10.0-15.6 GHz (43.8%), respectively, collectively covering the anticipated 5G-Advanced and 6G bands (6.425-15.35 GHz). Both the MB and HB antennas employ a planar magnetoelectric (ME) dipole structure to avoid common-mode resonances within the LB and MB and to minimize cross-band scattering in the HB. The proposed array maintains undistorted radiation patterns and better than 20 dB port isolation between any two ports across all three bands.

Figures (17)

• Figure 1: Configuration of the developed tri-band array.
• Figure 2: (a) Geometry of the tube and even spiral, (b) $|$MWC$|$ of the tube and even spiral, and (c) modal E-field distribution of Mode e2 and Mode e3.
• Figure 3: (a) Geometry and (b) $|$MWC$|$ of the segmented spiral.
• Figure 4: (a) Monostatic RCSs of the tube, even spiral, and segmented spiral. (b) Input impedance of the LB dipole using the tube or segmented spiral.
• Figure 5: Geometry of the LB segmented spiral antenna with integrated serial resonators and suppressors in the balun.