Patent ID: 9559605
Date: 2017-01-31
CPC Classifications: H02J,H02M

Claim:
1. An energy harvester to convert incident radio frequency (RF) energy associated with an RF signal to direct current energy, the energy harvester comprising: a first RF rectifier to output a first voltage determined by rectified RF energy in response to received RF energy; a first energy reservoir coupled to the first RF rectifier to store energy at the first voltage; a DC/DC converter coupled to the first energy reservoir to convert the first voltage to a second voltage; a second reservoir coupled to the DC/DC converter to store energy at the second voltage, the second voltage being greater than the first voltage; and a third reservoir coupled to the second reservoir to receive energy transferred from the second reservoir periodically and coupled to a load, wherein the third reservoir comprises a capacitor having a capacitance value chosen to control an amount of usable energy stored in the third reservoir as a function of an RF transmission duration, the impedance of the load, and a threshold voltage, the usable energy being a portion of the stored energy above the threshold voltage.