Performance Analysis and Design Guidelines of Single and Multi-PA Driving Architectures for 5.8-GHz RF-Based Wireless Power Transfer Systems

Abstract

This paper presents a comprehensive performance comparison between single and multi-power amplifier (PA) driving architectures for radio-frequency (RF) wireless power transfer (WPT) systems operating at 5.8 GHz. The conventional single-PA architecture relies on a high-power RF jammer module, suffering from low DC-to-RF conversion efficiency (<inline-formula> <tex-math notation="LaTeX">$\eta _{pa} =15$ </tex-math></inline-formula>-25%), and elevated insertion losses. To address these limitations, a multi-PA architecture is proposed in which each transmit antenna is independently driven by a dedicated low-power PA module, achieving <inline-formula> <tex-math notation="LaTeX">$\eta _{pa} =35$ </tex-math></inline-formula>-40% DC-to-RF conversion efficiency. Two complete hardware prototypes are developed and experimentally characterized: (1) a conventional jammer-based system and (2) the proposed multi-PA system. Under comparable total DC input conditions, the analytical model predicts load powers of 525 and 302 mW for the proposed and conventional architectures, respectively, at 1.5 m. At 3.0 m, the corresponding calculated values are 134 and 77 mW. The calculated load-power improvements are approximately 73.8% and 73.7% at 1.5 and 3.0 m, respectively. The measured results exhibit consistent distance-dependent trends and confirm the superior load-power capability of the proposed architecture.