Performance Improvement of a 2.4-GHz Multi-stage Rectifier Using Power Optimized Waveforms

This work reports the impact of using power optimized waveforms (POWs) in wireless power transmission (WPT) systems especially on the Cockcroft-Walton voltage multiplier developed for an electrostatic vibration energy harvester where the bias voltage has an important task to decrease the charging time of the capacitor plates. Several indicators such as peak-to-average power ratio (PAPR), instantaneous power variance (IPV) and complementary cumulative distribution function (CCDF) are calculated and used to predict the voltage gain of different waveforms compared to single tone signal. The simulations and measurements show the improvement of RF-to-dc conversion efficiency with POWs where 8-tone signal's voltage output is 1.6 V (2 dB of voltage gain) higher than 1-tone signal at 0 dBm.