Design and Experimental Validation of a High-Efficiency Cross-Polarization Converter for Microwave Power Transfer

This letter presents a high-efficiency cross-polarization converter (CPC) for microwave power transfer (MPT) applications. The proposed CPC efficiently converts a linearly polarized incident wave into its cross-polarized counterpart. Featuring an ultra-thin profile (∼0.056λ₀), the converter exhibits excellent integrability with microwave power transmitters. A prototype was simulated, fabricated, and experimentally characterized to validate its performance in polarization manipulation. Measurement results demonstrate a peak polarization conversion ratio (PCR) of 99.95%, approaching ideal performance. Furthermore, the calculations reveal a power loss of only 6.6% in the prototype. These features make it highly suitable for MPT applications. System-level MPT experiments indicate that the receiver can capture significant power when equipped with the proposed CPC, even under cross-polarization conditions between the transmitter and receiver. The maximum received power in this scenario reaches 92.5% of that achieved under co-polarization alignment.