Shielded Antenna for Wireless Power Transfer EMI Reduction
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Solution Overview
Problem
Wireless power transmitters face challenges in minimizing electromagnetic interference (EMI) and radio frequency (RF) interference while efficiently charging electronic devices, which can be inconvenient and harmful.
Innovation Solution
The implementation of a shielded antenna or resonator located off-center with respect to the wireless charging area, surrounded by shielding elements that diminish the wireless field outside the charging area, ensuring a stronger field within the charging area for efficient power transfer while reducing EMI and RF interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a wireless power transmitter generates a strong wireless field for efficient power transfer, then charging efficiency is improved, but electromagnetic interference (EMI) and radio frequency (RF) interference increase
Solution Approach 1:
The patent applies magnetic shielding materials to convert the harmful electromagnetic radiation into beneficial concentrated magnetic field lines within the charging area. The shielding elements redirect and concentrate the magnetic flux, transforming what would be harmful EMI and RF interference into useful power transfer energy, thereby improving charging efficiency while reducing external interference.
Solution Approach 2:
The patent introduces magnetic shielding materials as intermediary elements between the wireless power transmitter and the surrounding environment. These shielding materials act as a mediator that allows the magnetic field to pass through to the charging area while blocking and redirecting electromagnetic radiation outward, thus separating the useful power transfer function from the harmful EMI radiation.
2Object-generated harmful factors
If shielding elements are added to reduce EMI and RF interference, then harmful radiation is minimized, but device complexity increases
Solution Approach 1:
The patent employs thin magnetic shielding films and flexible shielding materials that can be integrated into the wireless charging device structure. These thin-film shielding elements provide effective EMI and RF protection while adding minimal structural complexity and maintaining device flexibility, thus reducing the impact on overall device design complexity.
3Object-generated harmful factors
If the transmit antenna is positioned outside the wireless charging area, then EMI is reduced, but field strength within the charging area decreases
Solution Approach 1:
The patent positions the transmit antenna in a different spatial dimension (outside the wireless charging area) and uses magnetic shielding elements to redirect magnetic field lines through the charging area. This dimensional repositioning combined with field redirection maintains strong field strength within the charging area while reducing EMI radiation to the external environment.
Solution Approach 2:
The patent creates different magnetic field qualities in different spatial locations: within the wireless charging area, the magnetic field is concentrated and strong for efficient power transfer, while outside the charging area, the shielding materials redirect and weaken the field to reduce EMI. This local differentiation of field quality resolves the contradiction between field strength and EMI reduction.
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 solution effectively minimizes unwanted EMI and RF radiation while maintaining a strong wireless field for efficient charging, enhancing the safety and convenience of wireless power transfer systems.
Implementation Method 1
at least one shielding element overlapping the transmit antenna on a side of the transmit antenna from which the device is configured to be positioned within the wireless charging area, the at least one shielding element configured to diminish at least a portion of the wireless field
Implementation Method 2
a transmit antenna configured to generate a wireless field to power or charge a load
Data Source
AI summary
An apparatus for wireless power transfer includes a transmit antenna configured to generate a wireless field to power or charge a load, a wireless charging area configured to receive a device to be wirelessly charged via the wireless field, the transmit antenna located outside of a periphery of the wireless charging area, and at least one shielding element overlapping the transmit antenna on a side of the transmit antenna from which the device is configured to be positioned within the wireless charging area, the at least one shielding element configured to diminish at least a portion of the wireless field such that the wireless field in the wireless charging area is stronger than the wireless field where the at least one shielding element overlaps the transmit antenna.