Abstract This paper investigates a waveguide-fed single-RF-chain antenna switching system (WASS) for 28 GHz millimeter-wave communications. The system uses eight reconfigurable coupling points distributed along a rectangular metallic waveguide and performs adaptive coupling-point selection through a threshold-based switching policy, without requiring multiple RF chains. A coupled-mode-theory-based model is used to describe frequency-dependent coupling and waveguide propagation, and the resulting system is evaluated by Monte Carlo simulations under representative indoor, urban, and fading environments. The results show that, under calibrated phase mismatch, the practical WASS preserves about 80.8% of the ideal coupling spectral efficiency baseline. It also maintains throughput above 1 Gbps at 300 m in the Wi-Fi 6 Indoor case and shows controlled performance degradation under mobility up to 200 km/h. Comparisons with 64-antenna massive MIMO and 128-element passive reconfigurable intelligent surfaces (RIS) indicate that the proposed single-RF-chain WASS remains considerably closer to the massive MIMO baseline than to the passive RIS benchmark under the considered Urban Micro scenario. These results suggest that WASS is a hardware-efficient and robust alternative for millimeter-wave access networks.
Yüksel Tokur Bozkurt (Mon,) studied this question.