Wideband 4-Port Patch Antenna Module Based Compact 8-Port Two-Module Antenna for 6G Upper Mid-Band 8 × 4 Device MIMO With Enhanced Spectral Efficiency

Abstract

For future or 6G international mobile communication (IMT) mobile services, the World Radiocommunication Conference 2023 (WRC-23) identified new frequency band 6.425-7.125 GHz and also recommended 7.125-8.4 GHz to be considered four years later in the WRC-27. It is thus envisioned that the wide frequency band 6.425-8.4 GHz (about 2 GHz bandwidth) in the upper mid-band is very promising to become the core frequency band for 6G mobile communication, which is expected to launch in 2030. This article presents the wideband low-profile (1 mm) small-size 4-port patch (4PP) antenna module covering 6.425-8.4 GHz and its application to form a compact 8-port two-module (8PTM) antenna for the mobile device. The fabricated 8PTM antenna is studied; moreover, it is applied as 8 receive antennas in the 8×4 MIMO system field test with 4 spatial streams. The 8PTM antenna shows its capability for the 8×4 device MIMO application with enhanced spectral efficiency (the extreme receive antennas-aided MIMO system). In this study, a measured spectral efficiency up to 37.3 bps/Hz or 9.33 bps/Hz per stream is obtained for the 8×4 MIMO operation, which is larger than those that have been reported for the upper mid-band device MIMO application. Details of the 4PP antenna module, the 8PTM antenna, and the 8×4 MIMO system field test in our campus indoor and outdoor public scenarios are presented.