Experimental Validation of a 3.45 GHz RF-to-DC Rectifier

This paper presents the design, fabrication, and experimental validation of a 3.45 GHz RF-to-DC voltage-doubler rectifier intended for sub-6 GHz wireless power transfer and RF energy harvesting applications. The proposed rectifier uses low-barrier SMS7630 Schottky diodes, a distributed microstrip impedance-matching network, and an FR4 substrate optimized for low RF input power operation. The design was developed using nonlinear Harmonic Balance simulations in Advanced Design System (ADS) and experimentally characterized through reflection-coefficient measurements, output DC voltage measurements, and RF input power sweeps. A quantitative comparison between simulated and measured results demonstrates good agreement in the impedance-matching characteristics, with a measured resonance frequency of 3.438 GHz and a minimum reflection coefficient of −25.22 dB. The fabricated prototype achieved a maximum measured output DC voltage of 1.58 V and a peak RF-to-DC conversion efficiency of 25.9% at an RF input power of +2.9 dBm. The experimental results validate the practical implementation of the proposed rectifier topology and demonstrate its feasibility as a proof-of-concept RF energy harvesting building block for ultra-low-power IoT and wireless sensing applications. The presented implementation also provides a solid foundation for future optimization using low-loss microwave substrates, improved matching networks, and complete rectenna integration.