Compact High-Efficient CPS 2.45 GHz Multistage RF-DC Rectifier for Wireless Energy Harvesting

Wireless electromagnetic charging becomes an important useful module for the internet of things (IoT) devices. The majority of commercial applications utilize the wireless radiofrequency (RF) charging in 2.45 GHz band. This frequency band ensures the design compactness of either the antenna or the rectification unit. In this study, a compact RF-DC rectifier operating at 2.45 GHz is investigated. The proposed rectifier employs a coplanar strip line (CPS) configuration and a lumped LC component used for the impedance matching. The CPS architecture is selected so it provides a balanced output DC voltage which is appropriate for directly supplying the CMOS circuitry of the IoT devices. The impedance matching is simply constructed using an L-section of reactive elements. To greatly enhances the output DC voltage, the rectifier is built using multistage voltage-doubler configuration. The performance of the rectifier is evaluated, and the measurements were compared with the simulation results. The rectifier efficiency is estimated over the frequency band from 1.8 to 3 GHz, and it indicates a flat response for the RF-DC efficiency. The peak efficiency of the rectifier reaches up to 53% over the band of interest. This rectifier can find several applications in wireless communication and IoT electronic circuits.