Modeling Piezoelectric Harvesters under Amplitude and Frequency Modulated Vibrations The prediction of the extractable power from energy harvesting devices is of utmost interest for system designers. In this paper, this issue is addressed in the case of Piezoelectric Resonant Vibration Energy Harvesters (PRVEHs) driven by amplitude and frequency modulated vibrations. The widespread architecture of PRVEH systems made up of a passive rectifier cascaded by a DCDC converter is here considered. An analytical expression of the harvested power as a function of the voltage at the output of the passive rectifier is derived for the cases of vibrations with amplitude modulation and frequency modulation. Further, an analyticalnumerical formula is presented for PRVEHs fed by nonsinusoidal vibrations exhibiting envelope and frequency with slow variations. Numerical simulations confirm the theoretical results.

A SolarThermoelectricTriboelectricVibrationRF Hybrid Energy Harvesting based High Efficiency Wireless Power Receiver This paper presents a RFSolarThermoelectricTriboelectricVibration hybrid energy harvesting based high efficiency wireless power receiver (WPR). The proposed WPR architecture incorporates a highpower path and a lowpower path maintaining high power conversion efficiency (PCE) over a wide input power range (xe2x88x9210 dBm to 30 dBm). Timedomain Maximum Power Point Tracking (MPPT) is proposed for SolarThermal Energy Harvester. High Efficiency Full Wave Rectifier (FWR) is designed for TriboelectricVibration Rectifier. A 5.8 GHz RF DCConverter with adaptive matching is proposed to increase the dynamic range of input power. The chip is implemented in  0.18 mu mathrmm  BipolarCMOSDMOS (BCD) process. The die area of the chip is 2.8 mm x 5.0 mm, including the pads. The highpower RFDC converter operating at 5.8 GHz frequency achieves a measured PCE of 76.9% at 30 dBm (1 W). The solar energy harvester achieves a peak PCE of 69.85%. The lowpower RFDC converters operating at 900 MHz and 2.4 GHz achieve peak measured efficiencies of 73% and 71.9% at 0 dBm (1 mW), respectively. The BuckBoost DCDC converter employed in the proposed WPR architecture achieves a peak measured PCE of 94.5%.