IP Library › Granted Patent US 12,676,511
Granted Patent B2
US 12,676,511 · App. 18/734,603 · Granted Jul 7, 2026

Ultra-low power beamforming wireless power transfer system

Inventor: Aatmesh Shrivastava (Weston, MA)
Assignee: Northeastern University
H02J50/20H01Q3/22H02J50/40H02J50/80
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Quick Facts
Patent No.
US 12,676,511
App. No.
18/734,603
Filed
Jun 5, 2024
Granted
Jul 7, 2026
Kind
B2
Examiner
KIM, TAELOR
Art Unit
2836
USPC
307/104
Abstract

Wireless power transfer (WPT) efficiency is enhanced using an ultra-low power (ULP) distributed beamforming technique. A phase and frequency offset correction technique is used for beam-forming optimization, a backscattering communication technique is used to reduce power over-head, and a new rectifier and MPT method is used for high efficiency RF-to-DC conversion.

Claims (10)

1 . A wireless power transfer (WPT) method for combining and transferring the radio frequency (RF) energy output of a network of RF energy transmitters to a remotely located energy receiver, the method comprising:

sensing, via an open-circuit rectifier of the energy receiver, received power from the RF energy transmitters, wherein the open-circuit rectifier senses the received power by producing an open-circuit voltage,

the open-circuit rectifier having circuitry electrically coupled thereto, comprising an analog-to-digital converter (ADC) electrically coupled to a bandgap reference (BGR) circuit and a crystal oscillator (XO), wherein the open circuit voltage, an output of the BGR and an output of the XO are input to the ADC to produce an indication of received power; and

correcting, in the RF energy transmitters, the phase and frequency offset among the RF energy transmitters based on the sensed received power.

2 . The method of claim 1 , further comprising generating, via a pulse generator electrically coupled to the ADC, backscattering pulses to transmit received power information to the RF energy transmitters to align transmitter phases.

3 . The method of claim 1 , further comprising converting the RF energy output from the RF energy transmitters to direct current (DC) using a self-biased gate (SBG) rectifier and operating the self-biased gate rectifier at a maximum power point.

4 . The method of claim 1 , wherein correcting the frequency offset comprises periodically changing the phase of one of the RF energy transmitters relative to another RF energy transmitter using a low-frequency (LF) oscillator.

5 . The method of claim 1 , wherein correcting the phase among the RF energy transmitters comprises introducing a delay to adjust a local oscillator (LO) phase in an RF energy transmitter.

6 . The method of claim 1 , further comprising correcting, in the RF energy transmitters, Doppler shift resulting from relative motion between the RF energy transmitters and the energy receiver.

7 . The method of claim 1 , wherein the open-circuit rectifier of the energy receiver and the circuitry senses the received power using less than 50 nW of power.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 19, 2026
From: SHRIVASTAVA, AATMESH
To: NORTHEASTERN UNIVERSITY
Reel/Frame 073831/0612 →
Continuity (3)
Division 17861603 · Jul 11, 2022
Provisional Application 63221694 · Jul 14, 2021
Related Publication 20240322605A1 · Sep 26, 2024
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