Antenna Geometry for Stable Wireless Power Transfer
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Solution Overview
Problem
Existing wireless power transmission systems experience unstable power transmission efficiency due to changes in the coupling factor between antennas when the position of one antenna moves relative to the other, leading to disruptions in impedance matching and reduced efficiency.
Innovation Solution
A wireless power transmission system is designed with a first antenna and a second antenna, where the second antenna is shorter in length in the moving direction than the first antenna, and the distance between the end portions of the first antenna and the second antenna is longer than the distance between the intermediate portion of the first antenna and the second antenna, ensuring a stable coupling factor and impedance matching even when the second antenna moves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the position of the second antenna moves relative to the first antenna, then the adaptability of the wireless power transmission system is improved, but the power transmission efficiency becomes unstable due to changes in the coupling factor
Solution Approach 1:
The patent applies parameter changes by deliberately designing the first antenna with non-uniform current distribution characteristics through its specific geometry (end portions with different current characteristics than intermediate portions). This geometric parameter design compensates for position changes of the second antenna, maintaining stable coupling factor and power transmission efficiency across different relative positions.
Solution Approach 2:
The patent implements local quality by creating different current distribution characteristics at different locations of the first antenna. The end portions are designed to have different current characteristics compared to the intermediate portion, allowing each region to contribute differently to the overall coupling, thereby stabilizing power transmission regardless of the second antenna's position.
2Device complexity
If the second antenna is made shorter than the first antenna, then the device complexity is reduced, but the coupling factor becomes more sensitive to positional changes
Solution Approach 1:
The patent changes the geometric parameters of the first antenna, specifically making it longer than the second antenna and designing it with distinct end portions and intermediate portions. This parameter design creates a current distribution pattern that compensates for the size difference, maintaining stable coupling factor despite the asymmetric antenna lengths.
Solution Approach 2:
The patent deliberately introduces asymmetry by making the first antenna longer than the second antenna and designing the first antenna with non-uniform current distribution along its length. This asymmetric design with differentiated end and intermediate portions creates a coupling characteristic that is less sensitive to the position of the shorter second antenna.
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 configuration maintains stable power transmission efficiency by minimizing changes in the coupling factor and impedance matching, preventing reductions in power transmission efficiency due to positional changes between the antennas.
Implementation Method 1
a first antenna and a second antenna that perform wireless power transmission with each other
Data Source
AI summary
A wireless power transmission system includes a first antenna, a second antenna configured to perform wireless power transmission with the first antenna, and a movement unit configured to move a position of the second antenna relative to the first antenna in a predetermined moving direction, wherein the second antenna is shorter in length in the moving direction than the first antenna, wherein a distance between at least one end portion of the first antenna in the moving direction and the second antenna at a position where the second antenna faces the end portion is longer than a distance between an intermediate portion of the first antenna and the second antenna at a position where the second antenna faces the intermediate portion, and wherein the intermediate portion of the first antenna is a portion of the first antenna excluding both end portions of the first antenna.