Microwave Power Beamforming Using Direct-Path DOA Selection
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Solution Overview
Problem
Microwave power transmission systems face interference issues due to radiation in directions other than the line-of-sight angle, particularly when signal paths include reflected waves, which can affect nearby radio equipment.
Innovation Solution
A power transmission device performs direction-of-arrival estimation on beacon signals to select the direct wave path and form transmission beams with directivity only in that direction, suppressing radiation in other directions to avoid interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If channel estimation is carried out using channel information that includes a plurality of signal paths (direct wave and reflected waves), then beamforming can maximize power shared with the power receiving device, but microwaves are radiated in directions other than toward the receiving device, causing radio interference with nearby equipment
Solution Approach 1:
The patent segments the channel information into multiple signal paths (direct wave and reflected waves) and processes each path separately. By identifying and selecting only the direct wave path for beamforming, the system transmits microwaves exclusively in the direction of the power receiving device, eliminating radiation in other directions and preventing radio interference with nearby equipment while maintaining maximum power transmission efficiency
Solution Approach 2:
The patent applies local quality by directing the microwave beam with high precision only toward the specific location of the power receiving device. Through direction-of-arrival estimation and selective beamforming on the direct wave path, the system concentrates power transmission in the required direction while suppressing radiation in surrounding areas, thus achieving efficient power transfer without causing harmful interference to adjacent radio equipment
2Power
If the line-of-sight angle from the power transmission device to the receiving device is parallel or nearly parallel to the ground surface, then beamforming can transmit power to the receiving device, but a high-power signal reaches distant radio equipment, leading to interference issues
Solution Approach 1:
The patent segments the transmitted signal into direct wave and reflected wave components, then selectively applies beamforming only to the direct wave path. This segmentation ensures that even when the line-of-sight angle is parallel to the ground, the high-power signal is directed precisely at the receiving device through accurate direction-of-arrival estimation, preventing distant radio equipment from being affected by stray radiation
Solution Approach 2:
The patent employs feedback through direction-of-arrival estimation to continuously monitor and identify the precise angular position of the direct wave path. By using this feedback information to adjust the beamforming weights, the system maintains accurate directional control of the microwave beam, ensuring that high-power signals reach only the intended receiving device and not distant radio equipment, even when operating at low elevation angles
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures efficient power transmission while minimizing radio interference with other wireless devices by focusing the beam on the direct path, reducing interference with nearby equipment.
Implementation Method 1
a transmitter configured to perform transmission beamforming of a power signal with directivity toward the selected direction of arrival
Implementation Method 2
a receiver configured to receive a signal from a power receiving device via a plurality of antennas
Data Source
AI summary
According to one embodiment, a power transmission device according to this embodiment includes: a receiver that receives a signal from a power receiving device via a plurality of antennas; a controller that detects a plurality of directions of arrival of the signal by performing direction-of-arrival estimation based on the received signal, and selects one of the directions of arrival; and a transmitter that performs transmission beamforming of a power signal with directivity toward the selected direction of arrival.