Wireless power transfer (WPT) has emerged as a promising technology for prolonging the battery life of energyconstrained devices. Waveform optimization enhances energy harvesting efficiency, but depends on the applied energy harvesting model. Conventional models capturing rectifier nonlinearities unveiled multisines’ superiority over continuous waves, but exhibit limitations in supported waveforms and rectifier structures. A recently proposed waveform-to-energy harvesting model addresses these limitations and showed that pulsed radio frequency (RF) signals outperform multisines under ideal conditions. However, practical deployments face channel uncertainty. This paper presents a robust optimization framework for WPT systems under a bounded channel estimation error model. We develop an efficient algorithm maximizing worst-case harvested energy and propose single- and multi-frequency pulsed RF designs that maintain performance despite channel uncertainty. Numerical results demonstrate significant gains of the proposed designs over benchmarks, especially under severe channel uncertainty.

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